I have bought all their records after the concert. I bought all their records after the concert.  Which one is correct? I understand when we use the present perfect and when the past simple, I just wanted to know if the expression 'after the concert' could also mean the period of time since the concert and up to the present day? Would that allow the use of the present perfect?
When is the present perfect tense used instead of the past tense?    I know that the present perfect tense is used when some adverbs (e.g., never, ever) are present in the sentence; the same is true for sentences like the following one.     When you returned, I have been at home since 3:00 PM.   In which other cases should I use the present perfect? Do the following sentences require it?     I have walked downtown everyday for a year.        I have been at home since 3:00 PM.
How to change the starting reference number in Natbib in a given bibunit? I'm using bibunit and Natbib packages with a numerical numbering.   \begin{bibunit}[plainnat]     \nocite{ref1,ref2}     \putbib[mybiblio] \end{bibunit}  \begin{bibunit}[plainnat]     \nocite{ref3,ref4}     \putbib[mybiblio]  \end{bibunit}   How can I set the starting number for ref3 and ref4 to be different from 1 (say 15), without affecting the starting number for ref1 and ref 2? The desired result is the following:   [1] ref 1 [2] ref 2 [15] ref3 [16] ref4 I honestly have no idea how to approach this question. I have done easier questions eg. show $gcd(a,b)lcm(a,b)=ab$ by letting $a=Alcm(a,b)$ and $b=Blcm(a,b)$ and then using the fact that $A$ and $B$ are coprime. However this approach only works in two variables. Any help with the question in the title would be greatly appreciated, as well as the thought process behind the answer so that I can approach similar problems. I tried to open Software Center using the command line   software-center   and it did work. I mean, Software Center opened and works fine, BUT, at the same time, in the Terminal window I see a lot of strange errors. How can that be? I'm puzzled.   Is there any explanation for this (and a fix for it)? I repeat, the app does open and it works fine, is only the lines in the background that show that something is not all right.  Here are the screen-shots with all the lines. What is the best way to copy a folder and all subfolders and files using c# How to find the sum of all the numbers that can be formed using the digits 2,3,3,4,4,4.. What should be the way of doing this type of problem?? Please guide Connected set in $\mathbb{S}^1$ Let $A$ be a connected set in $\mathbb{S}^1$. Show that $A^c$ is also connected.  My idea: suppose $A^c$ is not connected. Then, there exist $U,V \subset \mathbb{S}^1$ open and disjoint such that $U \cup V =A^c  $. Therefore $\mathbb{S}^1 = A \cup U \cup V$. If I had that $A\cup U$ was open I could arrive at  contradiction, since $\mathbb{S}^1$ is connected, but I can't say that... I want to produce four groups (high/high, high/low, low/high and low/low) using two continues variables and compare these groups in terms of a few dependent variables. I know that cluster analysis (k-means and hierarchical) is a type of 'end' analysis which is the main goal of the paper to reach such clusters and then discuss the nature of the clusters. However, I am willing to use this technique (k-means by using k=4) as a kind of preliminary analysis to produce the groups. I know that scatter plot and means splits are other alternatives but they have their own disadvantages that cluster analysis may resolve. What do you think? How do I disable System Integrity Protection (SIP) AKA "rootless" on macOs [OS X] How to use GROUP BY to concatenate strings in MySQL? Can you transfer a Windows 7 XP-mode VHD to a new PC without the need for reactivation? How to style text in hyperref \url? I want to set color, font and similar style attributes for the text in a \url from the hyperref package. How do I go about doing it? All I have found are . I want to because I am using ttf fonts for my texts and I want my urls to be in that ttf and not the default (typewriter font?) that the hyperref package gives me. I started with just trying to get it in italics but didn't even succeed with that:  \documentclass{memoir} \usepackage{hyperref} \begin{document} Lala \url{\itshape www.example.com}. \end{document}     I am guessing there is some hook or something but I just can't find it. Maybe I have gone blind? I've tried to read and understand this:   As a test, since my layout is "Polish, programmer" in the /usr/share/X11/xkb/symbols/pl file I played with remapping the 'q' character to 'x', and it worked just fine.  But what I want, is to remap LWIN (Left Super) to Left Control.   So I tried this: I started editing /usr/share/X11/xkb/symbols/pc file, assuming this is the 'root' of all the other files. Commented out this line:  //key &lt;LWIN&gt; {  [ Super_L       ]   };   and added this one:  key &lt;LWIN&gt; {    [ Control_L     ]   };   and rebooted PC, with no success. I.e. LWIN + C, doesn't copy selected text in text editors to clipboard, instead it just produces the 'c' letter. In the terminal instead of stopping current programm it also just produces the 'c' letter.  Here is my config file:   When I try the xev command and then press the Left Control Key, I see this:  KeyPress event, serial 40, synthetic NO, window 0x5a00001,     root 0x7e, subw 0x0, time 1053321, (374,-259), root:(374,545),     state 0x0, keycode 133 (keysym 0xffe3, Control_L), same_screen YES,     XKeysymToKeycode returns keycode: 37     XLookupString gives 0 bytes:      XmbLookupString gives 0 bytes:      XFilterEvent returns: False  KeyRelease event, serial 40, synthetic NO, window 0x5a00001,     root 0x7e, subw 0x0, time 1053425, (374,-259), root:(374,545),     state 0x0, keycode 133 (keysym 0xffe3, Control_L), same_screen YES,     XKeysymToKeycode returns keycode: 37     XLookupString gives 0 bytes:      XFilterEvent returns: False   BTW. Ask ubuntu suggests me two links to similar questions, but they are old, and suggest using xmodmap, and afaik it's no longer correct answer on Ubuntu >= 16.04 (Xenial) and this is precisely the version I have.  BTW2. I would really like to avoid using apps like Xbindkeys, considering there is a built in solution, which I guess I almost understand, and already spent some time on trying to understand it. The nautilus-open-terminal package adds a menu/right-click option to open a terminal in the current directory.  I want to change this from opening gnome-terminal to opening terminator. , however these instructions do not appear to be valid any more, and I can't find any place in the system settings where the default emulator can be changed.  I also tried:  $ sudo update-alternatives --config x-terminal-emulator   choosing  * 0            /usr/bin/terminator               50        auto mode   But this does not appear to have any effect. Any idea how I can get this to work? Notation and the name choice for meet and join (in order theory) I have two simple questions:   From where do the names  come from? I don't see any intuition between those names in context of order theory. From where does the notation come? I have to admit, I always had an impression that notation we use is somewhat backwards... just take the look at the picture at the wikipedia!    I used this notation a lot of times and I have to admit that often I have to stop for a minute and convince myself that I'm indeed using it right. I'm hoping that learning a bit about origin and context of name choice and notation will make it easier. I've just returned from several unusual countries in Asia, and annoyingly despite being told I'd have no problem, I'm unable to find anyone in London to change back to pounds.  I've tried Travelex in Heathrow, a currency exchange place, and the post office.  The currencies include cash from: Mongolia, Kyrgyzstan, Kazakhstan and Uzbekistan.  Most of the responses when shown the money is to the tone of "What the hell currency is this?" which doesn't fill me with confidence.  Any suggestions welcomed for places that may change this. Otherwise I may need to go back next year ;) How to make skill use on investigations "important" but failure not derail the plot? Well guys, following previous recommendations here I was able to build a Horror Themed Savage Worlds campaign that has made my players excited. However they're still getting used to the style, as well as I am. In order for them to hurt the major evils of the adventures they have to find their Form (physical appearance, name), Truth (How the creature came to be) and Reason (What the creature wants to), so they have to do research, kill lesser creatures, and run away from the big baddie of the adventure as they seek what it is.  Well, this is my problem:  How can I make them use skills significantly?  I'm used to railroading my players, even with mysteries, and I don't know how to put their skills for significant use. An example is, they usually require Streetwise or Investigation to gather clues and such, however, I wonder what to do if they fail the roll... If they fail they're not supposed to find anything, so chances they never finish the adventure are well, high, that and I have no idea how to give them additional, interesting ways for them to find the truth. So do I give it no matter what they rolled? How do I make use of their skills important and not just busy-work without having a failure on a roll completely stop their progress in the investigation? Uninstalling/reinstalling QGIS plugin where uninstall is disabled? Plugin Raster->TerrainAnalysis->slope which had initially worked, started showing what another questioner referred to as a "crazy histogram":   Before finding his question and the answer, I endeavored to uninstall and reinstall the plugin.  I found/still find (QGIS 2.0.1, now upgraded to QGIS 2.4, on Ubuntu 14.04), the plugin "uninstall" button grayed out/disabled.  It's working, but I am worried about having a plugin I installed that does not offer an option to be uninstalled.  Failing anything else I would be tempted to use the path information to rename the .so library and see if it disappeared. Short story, domed refuges Prove that $Z(G)$ which is the center of $G$ is a subgroup of $G$ How could a gap between array modifier created objects be closed?