["I had to take a test in order to graduate college but I really didn't understand the subject at all and couldn't get anywhere studying on my own. After a lot of agony my sister sat down with me and went over it in detail. She really helped me to learn and understand it. Thanks to her I got a great score on the test!", 'That is very nice of your sister!', 'I thought so. I really am so happy with her. Do you think I should do something nice for her in return?']
Yeah, maybe you should get her a gift of some sort.
There was a test that I needed to pass in order to graduate college. I was having so much trouble understanding the subject and really didn't feel like I could do it on my own. My sister sat down with me and really went over the whole thing allowing me to finally understand it and get a great grade on the test!