1.This film is not so good as ____ we saw last week.
A. that B. it C. the one D. one
2.I prefer a street in a small town to____in such a large city as Shanghai.
A. that B. it C. this D. one
3.He was late for school._____ made the teacher angry.
A. It B. This C. That D. there
它们的答案分别是1C, 2D, 3C; 我选的答案是1A, 2A, 3A 请老师帮帮我，解释一下为什么？谢谢！

1. C the one替代film，
整个句子相当于This film is not so good as that film，但是句中不能同时出现两个film，所以就用the one替代film。
we saw last week.是定语，修饰the one。

2. D that替代前面出现过的a street
3. C这里的that用于替代前面出现的句子

这是个one和that的区别练习

one和that是代词，用来替代上文出现过的名词，以避免重复

One用于替代可数名词，复数形式为ones。
That用于替代可数名词单数或者不可数名词，替代复数时用those
如：
I like white flowers，while she likes red ones.有形容词修饰时用one或ones
The air outside is fresher than that in the room。That替代不可数名词
The two boys work harder than those over there。Those表示 那些人
但是明显地表示“一个”的概念时，一定要用one