–Canyougoswimmingwithusthisafternoon?      --Sorry,Ican...

問題詳情：

–Can you go swimming with us this afternoon?

       --Sorry, I can’t. I _____ take care of my little sister at home because my mother is ill.

       A. can             B. may             C. would           D. have to

【回答】

D

知識點：情態動詞

題型：選擇題