根据句意及首提示完成下列句子。

1. The students in this school usually wear u        on weekdays.

2. We can e       in the dining hall every day.

3. There are many chairs and desks in the c        .

4. You can't f      _ with your classmates.

5. There are r      _ everywhere.

上消化道出血可见 （）

A.脓血便

B.鲜血便

C.柏油样便

D.灰白色便

E.稀糊状便