1.I am sorry that I couldn't call you ealier.(couldn't 可以用ca

来源：学生作业帮编辑：作业帮分类：英语作业时间：2024/09/15 01:34:10

1.I am sorry that I couldn't call you ealier.(couldn't 可以用cannot 代替吗）
2.You can install windows frames which could make...
can可以用could代替吗
could可以用can代替吗

楼上的回答很完整了,好像你是在第二个句子的理解上有难度.
我看到过can和could表示推测或可能性时的区别,刚好可以解释第二个句子,跟你分享一下.
1、表示理论上的可能性(即从理论上分析是可能的,但实际未必会发生),两个词都能用.
只是 can表现在,而could表过去：
现在：He is in poor health.He can be ill at any time.他身体不好,随时都可能会生病.
过去：My mother could be very unpleasant at times.我母亲有时候会让人非常不愉快.
2、表示现实可能性：一是指将来可能性,一是指现在的可能性,在这两种用法中,通常都不用 can,但可用 could：
例如：We could go to Japan this summer.今年夏天我们可能要去日本.(将来可能性)
这里就不能用can了,用can会变成“能够”的意思,而不是“可能”.
can有时也用来表示现在的可能性,但那通常只限于否定句或疑问句中：
比如：It can’t be true.那不可能是真的.
希望能帮到忙~.

1.I am sorry that I couldn't call you ealier.(couldn't 可以用ca I\'m so sorry that i couldn\'t follow through I am sorry I couldn't hear you clearly.Please r____ your qus “Sorry I couldn't get back to I couldn`t help i couldn‘t是什么意思 I couldn't help i couldn't agree The box was so heavy that I couldn't lift it .中为什么用couldn't — Oh,sorry,I'm late.I couldn't remember ________.— That's al I had to say sorry for the love that i couldn't respond , i couldn't agree with you more.