come about : 发生，造成 相当于happen

When Mother woke up, she didn't know what had come about.

I'll never understand how it came about that you were late three times a week.

Do you know how the air accident came about?

3. There is no doubt that....

一、作不可数名词,作"疑惑;怀疑"

①肯定句中doubt多接whether (一般不用if代替) 同位语从句。如:

There's some doubt whether he'll keep his promise. 他会不会信守诺言还难说。

She had her doubts whether the new book would sell well. 她怀疑新书是否会畅销。

②否定句中doubt多接that同位语从句。如:

There is no doubt that they will ask you for help. 毫无疑问,他们会请你帮忙的。

I have no doubt that you will succeed. 我毫不怀疑你会成功的。

二、作及物动词常用于下列句型中,作"怀疑;不能肯定;不大相信"解,一般不用进行时态。

①用于否定句或疑问句,后接that引导的宾语从句。如:

I don't doubt that he is telling the truth.

我毫不怀疑他在讲真话。

Do you doubt that he will win the match?

你怀疑他会赢这场比赛吗?

②用于肯定句,一般接whether 或if引导的宾语从句.如:

We doubt if she will be persuaded.

我们不知道她会不会被说服。

4. He found that the amount of carbon dioxide keep on increasing during that time.

习惯用语：

an amount of 相当数量的; 一些 修饰不可数名词

amounts of 相当数量的; 一些 修饰不可数名词

large amounts of money 大量的金钱

②keep on 继续 +doing sth.

他们虽然很累了，还是继续工作。

They keep on working although they are tired.

5. result in

result in 结果; 致使; 导致

主语：起因 in 的宾语：结果

Acting before thinking always results in failure.做事不先考虑总会导致失败。

The accident resulted in the death of two people.这场意外事故造成两人死亡。

result from 起于, 由于, 由...引起，