—How long did he play the piano? (    )
—He played the piano __________ about half an hour.

A．with

B．to

C．for

—What can this robot do? (    )
—__________

A．He can play the piano.

B．He could sing a song.

C．He will work out the problem.

—What __________ you __________ in the museum? (    )
—I __________ some insects.

A．did; see; see

B．did; see; saw

C．do; see; saw

There are many __________ paintings in the art museum. (    )

A．kinds

B．kind

C．kinds of

用所给词的正确形式填空。
【小题1】They visited “The World of Robots” on the __________ (two) floor.
【小题2】Alice is good at dancing. She is a good __________ (dance).
【小题3】Peter __________ (buy) a model plane yesterday.
【小题4】He __________ (can) eat five hamburgers a day ten years ago.
【小题5】Horses can run very __________ (fast).