The exercises are too hard. I don't think he can finish ________ them in an hour.

1. A.
   do
2. B.
   to do
3. C.
   doing
4. D.
   does

The exercises are too hard. I don't think he can finish ________ them in an hour.

[　　]

After you finish the exercises, you’d better have your answers ___________.

A. checking            B. checked                          C. to check               D. check

The students have ________ many exercises that they can't finish ________ in time.

1. A.
   so；them
2. B.
   so；it
3. C.
   such；them
4. D.
   such；it