题目内容
.Your son has kept _________ for two hours. You’d better ask him to have a rest.
A.study | B.studied | C.to study | D. studying |
D
keep doing 保持不间断地做某事
keep to do keep要求 -ing, 没有 to do 形式
故选D.
keep to do keep要求 -ing, 没有 to do 形式
故选D.
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