【上期回顾】

【本期内容】

一、内容纲要

二、内容简述

（一）定义

用表示条件的连词连接一个句子，充当另一个句子的条件状语，这个句子就叫做条件状语从句。

常用来连接条件状语从句的连词有：if; unless; so long as; on condition that。

（二）if

表示“以便；为了”，如：

I will only stay if you offer me more money.

You can stay for the weekend if you like.

If you see him, give him this note.

If I were in charge, I would do things differently.

They would have been here by now if they had caught the early train.

（三）unless

表示“为了；以便”，如：

You won't get paid for time off unless you have a doctor's note.

Unless something unexpected happens, I will see you tomorrow.

The theatre faces closure unless it gets an urgent cash injection.

（四）so long as

表示“生怕；以免”，如：

We are sure to win the match so long as we go all out.

We don't mind who gets the credit so long as we don't get the blame.

The president need not step down so long as the elections are held under international supervision.

（五）on condition that

表示“以免；以防万一”，如：

They agreed to lend us the car on condition that we returned it before the weekend.

We will sign the agreement on condition that not a single word of racial discrimination is written into it.

You may use my bike on condition that you return it tomorrow.

（六）其他方式手段

如：

Supposing you are wrong, what will you do then?

Provided that we get support from them, we will win the match.

Suppose flights are fully booked on that day ─ which other day could we go?