be trained on 如题

be trained on 如题 be trained A,training B,trained C,being trained ,D,to be tA,training B,trained C,being trained ,D,to be trained 为什么选B不选D啊 should animals be trained yo help humanswhy? Should Animals Be Trained to Help Humans Should animals be trained to amuse human? Before she left on the trip,she __________ hard.A.had trained B.has trained C.would trained ______for weeks ,she could drive the bus.A.To be trained B.Having trained C.To have trained D.Having bee trained 为什么选A 英语翻译testman can’t be proved trained.testman can’t be proved who is trained.testman can’t be proved to be trained. Before she left on the trip ,she had trained hard. 1.Should animals be trained to amuse human beings? 跪求以下英语阅读理解的正确答案Many employers are convinced that you can be trained on the job to perform specific tasks but,after college,you cannot be trained to communicate well.One company official even concludes,If a candidate doe 几道专四的语法题,在线等答案,还有请告诉我为什么好吗,谢谢.急1,No one can walk the wire without a bit of fear unless ____ very young. A having been trained B trained C to be trained D being trained2,Having 一道简单的非谓语动词题The dog,______,will be made a good watch dog.A.trained properly.B.being trained properly.两个都可以选.理由：A.trained过去分词作状语.这条狗,由于受过良好训练,会成为一条好的看门狗.B.b 搞不懂-ed分词,-ing分词,不定式分词这三种形式的辨析,做题的时候老是出错!No one can walk the wire without a bit of fear unless _____ very young.A.having B.trained.C.to be trained D.being trained kept trained 最好可以解释如何用…… All the players in the football team must be (trained)five time a week.这里为什么要用trained No one can walk the wire without a bit of fear unless _______ very young.A.having been trained B.trained C.to be trained D.being trained我想选A,A对吗,为什么?