I know for certain that he's in here，but he won't answer me

我肯定他就在里面，但他就是不回答我。

(2)make certain弄清楚，弄确实

Make certain when the train leaves. 弄清楚火车什么时候离开。

中华资源库(3)be certain to do sth.一定会做某事 She is certain to come. 她一定会来。

(4)be certain of sth.确信...... I'm certain of your success. 我确信你会成功。

(5)adj.某(种)

A certain Mr Jones called while you were out.

＝ Mr Jones called while you were out.

 你出去的时候有个琼斯先生打电话来过。

注意：certain既可用人作主语，也可用物作主语，而sure一般用人作主语。

 It is certain that the earth is round. 毫无疑问，地球是圆的。

2、absence n．不在某处，缺席

(1)in the absence of sb.＝in one's absence某人不在时 absence of mind心不在焉

(2)absent adj.不在的，缺席的 be absent from...不参加...

 ①His during driving nearly caused an accident.

 他驾车时心不在焉，差点肇事。

 ②They spoke ill of the captain .他们在背地里说队长的坏话。

 ③Tom school because he was ill. 汤姆因病没去上学。

3、imagine v．想像

(1)imagine that/what/how/why...想像...... imagine doing sth.想像做某事

 imagine sb.doing sth.想像某人做某事 imagine sb./sth.as把某人(物)想像成......

 You can't imagine...你想像不到......

(2)imagination n．想像力，创造

 ① I can lend you money every time you need it！

　　　中华资源库你甭想每次你需要钱我都会借给你！

 ②I can't in such a place alone.

 我无法想像独自一人生活在这样的一个地方。

4、circumstance 环境；情况(常用复数)

 in/under the circumstances在这种情况下；情况既然如此

 in/under no circumstances 决不，无论如何都不(放句首时主句用倒装语序)

① he felt unable to accept the job.

 在这种情况下，他觉得无法接受这项工作。

② should you go alone. 无论如何你都不能单独去。

5、apologise (同apologize) vi.道歉，认错

 apologise to sb.for sth.为某事向某人道歉

　　apologise to sb.for doing sth.为做了......向......道歉

e.g. Bill his friend having kept her waiting for a long time.