.．When Icame into the classroom , I found him _______ with his study.

The baseball is _____ the floor _____ thedesk．

The teacher gave the books to all thestudents except _______who had already taken them.

Why do you look so upset—There are so many troublesome problems____.

.—- She was late for the party. —- That’s _________ she had forgotten the exact time.