每课一句：新概念英语第1册第125课
【往期回顾】
接下来，我们就来看看第125课的“每课一句”。
一、课文原文
Lesson 125 Tea for two
Can’t you come in and have tea now, Peter?
Not yet. I must water the garden first.
Do you have to water it now?
I’m afraid I must. Look at it! It’s terribly dry.
What a nuisance!
Last summer it was very dry, too. Don’t you remember? I had to water it every day.
Well, I’ll have tea by myself.
That was quick! Have you finished already?
Yes. Look out of the window.
It’s raining. That means you don’t need to water the garden.
That was a pleasant surprise. It means I can have tea, instead.
——选自《新概念英语》第一册，外语教学与研究出版社，1997年10月第1版
二、每课一句
I had to water it every day.
本课学习的是情态动词的用法，主要对比have to与must以及need与must的区别。
需要注意的是have to是按照实义动词的用法来使用的，它有人称和数的变化，也有时态变化。如：
I have to go and cook the dinner.
Look. The train's in. We'll have to run for it now.
To work out a plan, one has to start with investigation.
She has had to cancel her trip because of illness.
与must相比，must侧重表示主观上觉得必须，而have to表示客观上不得不。
【注意】
因为have to是按照实义动词的用法来使用的，所以其否定句和疑问句也是要按照实义动词的要求来变化的。如：
You don't have to go now.
Do you have to water it now?
三、更多拓展
That means you don't need to water the garden.
need被称作半情态动词，因为它既可以用作情态动词，也可以用作实义动词。
当用作情态动词时，大多用于否定句，作为must的否定表达，其基本用法为：sb./sth. needn't do sth.。如：
You needn't talk to anyone if you don't want to.
当need用作实义动词时，有人称、数和时态的变化，其基本用法为：sb./sth. need to do sth.。如：
It is a demanding role and she needs to work hard at it.
I'm sure I don't need to do this.
Do you need to drag yourself to work every morning?
need也可以用作：sb./sth. need sth.。如：
Your hair is all right; it's just that you need a haircut.
