Many people agree that___knowledge of English is a must in___internation trade today.

问题描述:

Many people agree that___knowledge of English is a must in___internation trade today.
为什么第一个要填a,第二个不填阿?

a knowledge of sth 是固定用法指对于某事的掌握.
第二个空若有冠词则是对于trade的,这里显然不能用a,而the也不对,因为它不是特指某商业交易.internation trade 内贸