( )you should ______do the work well. A.be able to B.can C.must D.are able to
问题描述：
( )you should ______do the work well. A.be able to B.can C.must D.are able to
答
A.be able to
答
A.should情态动词后只能用动词原型,can,must,本身也是情态动词,只能放在谓语位置,不能用在其他情态动词后,are的原形是be