A ballet dancer must____for a long period of time before she can sense her own center and balance herself.
问题描述：
A ballet dancer must____for a long period of time before she can sense her own center and balance herself.
A.trained B.have trained C.be trained D.be training
希望能把ABCD都分析下 并解释下句子的意思
答
A trained 不对,因为跟在must后要用动词原形,而trained是过去时
B have trained 不对,因为must have的意义是对过去发生事情的猜测
C be trained 正确,因为培训是别给给芭蕾舞者的,而不是她自己给自己的,所以要用被动语态
D be training 不对,这是进行/将来时,应该用被动语态
翻译：芭蕾舞演员必须经过很长时间的培训后,才能对把握和平衡自已.