问题补充：
After all of us finished our homework, the teacher told us at once.
A. to hand it in
B. hand them in
C. to hand them out
D. hand it out
答案：
(答案→)A. to hand it in
B. hand them in
C. to hand them out
D. hand it out
解析：选项中hand in是交上，hand out是分发。题目说完成作业后，所以应该是上交作业，用hand in；而tell的用法是tell sb. to do sth.所以本题应选A。
