17.—He can write well.
---He_____, but he doesn’t. He’s too lazy.
A.must B.mustn’t C.can D.can’t
18.—Did you do __________ on vacaton?
---Not really. I just stayed at home and helped mom.
A. something special B. anything special C.something serious D.anything serious
19.--________do you go to the dentist?
--Let me see, twice a year, maybe.
A.How many B.How much C.How often D.How soon
