简单改错

1.from改成since，现在完成时中，加一段时间用for或者since，这里表示“自从…”，所以用since。from不用在现在完成时中
2.when改成that，when是伴随状语，原句表达的并不是“当……，发生了……”，所以用连词that，不用when
3.which改成that，固定短语，只用that
4.are改成is，不看trousers，看this pair of，指一条，用单数
5.from改成with，begin with sth.是固定搭配，意为“以……开始”

1.He left home last year and I haven't seen him SINCE then.
时间"自从那以后"要用SINCE
2.It was yesterday when he broke the window.
没错
3.This is one of the most exciting football games THAT I have ever seen.
ONE OF 的定语从句只能用THAT 引导
4.This pair of trousers IS mine.
看做单数处理
5.Generally speaking,when a child learns to read,he usually begins WITH A,B,C.
BEGIN WITH固定搭配, "从……开始”

1.He left home last year and I haven't seen him since then.
2.It was yesterday THAT he broke the window.
It was...that强调句型
3.This is one of the most exciting football games THAT I have ever seen. 前面有one of 修饰时定语从句不用which要用that
4.This pair of trousers IS mine.
This pair of 中pair是单数
5.Generally speaking,when a child learns to read,he usually begins WITH A,B,C.
固定搭配：begins with