36 / PART ONE: THE BASICS If commas are missed out, the sense of the sentence is some- times lost or it has to be read twice. Sometimes the meaning can be changed by the placing of the comma. Look at the following: As mentioned first impressions can be misleading. The positioning of the comma could change the meaning: As mentioned, first impressions can be misleading. As mentioned first, impressions can be misleading. Using commas before questions Here is another example of the use of a comma: I don’t like her dress, do you? A comma is always used before expressions like ‘do you?’, ‘don’t you?’, ‘isn’t it?’, ‘won’t you?’ These are usually used in dialogue. There will be more about this in the next chapter. ‘You will come to the play, won’t you?’ ‘I’d love to. It’s by Alan Ayckbourn, isn’t it?’ Using commas before names A comma should also be used when addressing a person by name. This would also be used in dialogue: ‘Do be quiet, Sarah.’ ‘John, where are you?’