if only的意思是：但愿，要是……就好了。常引导虚拟语气。only if的意思是：只要……。引导陈述语气的真实条件句。

【例句】Only if you study word, you will pass the exam.

If only I had not been late yesterday.

3. be about to do, be to do 与be going to

be about to do 表示即将发生的动作，不表示按计划安排的活动，不与表示将来的时间状语连用。be going to 表示“打算/计划做某事”，它表示按计划安排要发生的事或者有迹象表明某事要发生。be to do 表示“按计划或打算要做的事”或者表示“要求、命令、禁止、注定等”。它所表示的动作是事先安排好的受到人的主观意识的控制。

【例句】He was about to leave when the telephone rang.

It is going to rain.

You are to do your homework in ink.

4. like与as做介词时的区别

like与as它们两个都可以做介词用。但like的意思是：像;类似;后接名词、代词或动名词。而as的意思是：作为，当作，当某人是(某身份)时。

【例句】I’ve always wanted a garden like yours.

As a child, he lived in India.

5. take, spend, cost与pay的区别

spend 的主语必须是“人”，宾语可以是“钱、精力、时间等”，其后用on+名词或者in + doing，in可以省略。cost 的主语必须是“物”或“事”，表示“费用，耗费”，后接life , money, health, time , money等，侧重于“花费”的代价。 take 表示“花费”时，其主语一般是“一件事”，通常用it做形式主语。pay 的意思是“支付”，宾语可以是“人、钱”等，常和介词for搭配。

【例句】The money he spent on the books added up to 500 yuan.

It took me five hours to finish the work.

The money I paid for the clothes was 800 yuan.

How much did it cost ?

【模拟试题】(答题时间：60分钟)

一、请从每道题的四个选项中选出一个最佳选项。

1. —Why don’t you put the meat in the fridge?

—It will __________ fresh for several days.

A. be stayed B. stay C. be staying D. have stayed

2. It’s time they_____________ to school.

A. go B. will go C. went D. have gone

3. I was having ________ time that I didn’t want to leave.

A. such a nice B. so nice C. such nice a D. such nice