小学英语句型转换This is the film .I saw it yesterday .(将两个句子用that合并成

This is the film that I saw yesterday.
这是一个定语从句,用that引导.
在这个句子中,也能把that换成which【注意：很多情况下that和which是不能互换的】
而从句的主语是I,所以that是作宾语,能省略
因此这个句子也能这么说
This is the film which I saw yesterday.
This is the film I saw yesterday.