...____not be a policeman, for he is much too short.请问老师这里用could和can都可以吗?两者意思有什么区别?另外couldn't have done 和 can't have done 是否都表示对过去事物否定推测?如果是,什么时候该用couldn't have done 什么时候又该用 c...
名词和形容词并列起来作定语:science and educational films;country and western music;arts and cultural affairs;sports and social facilities麻烦老师详细讲解一下以上语法现象,名词和形容词作定语,它们的性质是不同的,在一个短语中(用以上例子...
在表示“本不必做,但做了”,和 ”本不必做,也确实也没有做“时,是否只要动词have done 和 do之间改变就可以,而 need not 和 did not need to 随便用哪个都可以吗?need not have done / need not dodid not need to have done / did not need to...