18. I suggest that we ________ some money for poor children.

A. raise           

B. to raise

C. raised

D. raising

19. If you explained it to him more slowly, he ________ it.

A. understands

B. would understand

C. understood

D. will understand

20. Many students enjoy ________ part in outdoor activities.

A. take

B. to take

C. taking

D. took