英语差生有问

问题描述:

英语差生有问
I was told that there were about 10 foreign students studying Chinese .
请问为什么用studying?而不是study 或studied 或 were studying

there be句型中有系动词be,所以要用动词 的ing形式,句中的系动词是were,系动词不能加动词原形,加过去分词表示被动的含义,句中没有这样的意思,至于were studying 是错误 的用法,两个系动词怎么能连用呢?