A duck swim in the river A./ B.is C.can 选择哪个
问题描述：
A duck swim in the river A./ B.is C.can 选择哪个
A duck （ ）swim in the river
答
can ,因为can是情态动词,后面的动词能跟原形
A duck swim in the river A./ B.is C.can 选择哪个
A duck （ ）swim in the river
can ,因为can是情态动词,后面的动词能跟原形