She can't ________ in the lake.
A.swimming B.swiming C.swim
（）I _____the name of a friend.
A. write B. writing C. am write
（）There is _____ big bird in the tree.
A. a B. an C. the
（）Why are you _____ ?
A. laugh B. laughing C. sing
（）Why do you _____cups on your heads?
A. have B. having C. had
（）It’s easy _____make mistakes with English words.
A. to B. for C. of