根据对话内容及首字母提示，填入适当的单词完成对话。

A: Why do you look u 1 these days?

B: Because I f  2  in the biology exam the day before yesterday.

A: Is it true? I feel very sorry for you.

B: I don't care a 3 the grade, but I didn't find out why I failed the exam.

A: Did you study hard for the exam?

B: Yes, I s 4 the whole weekend on my lessons.

A: You'd better ask the teacher for some a  5  .