children can be instructed in swimming at a very early age.
问题描述:
children can be instructed in swimming at a very early age.
children become expert at holding their breath under water even before they can walk.在第一个句子里,是用in,代表,在什么什么方面,第二个句子里,是用at代表在什么什么方面,请问这两个词的区别是什么,可以相互用吗,他们什么时候,什么在什么情况下使用
答
其实你check一下in和at在词典上的用法即可知,或者搜索一下“in和at的区别”.这里是动词短语的固定用法问题,be instructed in,be expert at
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