The girl that we saw yesterday was Jim's sister.和Yesterday we saw a girl who was Jim's sister.
问题描述：
The girl that we saw yesterday was Jim's sister.和Yesterday we saw a girl who was Jim's sister.
答
第一句强调的是那个女孩，而第二句则是强调昨天看到过一个女孩这件事
答
第一个定语that we saw yesterday 修饰The girl
第二个定语who was Jim's sister修饰Yesterday we saw a girl
我不是高手，楼主见谅。。。应该没有错，但是错了千万别怪我......
答
第一句that引导的定语从句是修饰the girl的,见下：The girl (that we saw yesterday ) was Jim's sister.
第二句中who引导的定语从句也是修饰a girl的,没什么较大差别.只不过第二句好像不太符合语言习惯,感觉只讲了半句话,是你自己想的么?
答
没区别，一样意思，只是位置不一样,