be（兼指am，is，are，was等）
1.be是系动词，如在He is a good man里，也是助动词，如在He is respected by all里。但一个词不该同时用作系动词和助动词，所以不可说He is a good man，and respected by all，这里and后面该加上is。
2.下面各句都用There开首：
- There is a book on the desk.
- There are two books on the desk.
- There are a few books on the desk.
- There are some books on the desk.
- There are many books on the desk.
- There are several books on the desk.
A book is on the desk, Two books are on the desk等都比较少见。
3.be＋及物动词的过去分词成为被动语态。例如：The book is read every day. 注意只有及物动词才有被动语态，be＋不及物动词的过去分词仍然属于主动语态，那过去分词有形容词性质，如He is come和He has come意思相仿，不过前者着重“已到了”的状态，后者着重“已到了”的动作罢了。可以跟be用在一起的不及物动词的过去分词现在有gone，come，arrived，returned，fallen，grown等。从前got和become也往往这样用，现在却不普通。
4.比较下面每组里的两句：
- The report ought to be typewritten.(这报告应该用打字机打。)
The report ought to be being typewritten.(这报告应该现在正在打字中。) - The children will be dressed by eight o’clock.(孩子们最迟在8 点钟衣服就将穿好了。)
The children will be being dressed by eight o’clock.(孩子们最迟在8点钟将正在穿衣了。) - I hope I shall not be disturbed during the holidays.(我希望在假期里我将不被打扰。)
I hope I shall not be being disturbed during the holidays.(我希望在假期里我将不常被打扰。)
5.比较下面每组里的两句：
- He is polite.(他是有礼貌的样子的。)
He is being polite.(他正在装出有礼貌的样子来。) - She is angry with you.(她跟你发怒了。)
She is being angry with you.(她正在做出跟你发怒的样子。) - I am fair to both sides.(我对双方是公平的。)
I am being fair to both sides.(我正在留意做到对双方公平。) - You are an angel,(你是个好人。)
You are being an angel.(你现在这样待我真是个好人。)
比较下面三句：
- You are insulting him. （你正在侮辱他。）
- You are insulting to him. （你对于他是侮辱的。）
- You are being insulting to him. （你正在故意对他侮辱。）
6.be（这里只指be这个词）用在以if引导的从句里现在很不普通，通常改用陈述语气，如If it is...。但Though...be...现在仍然普通，这因为Though...is...和Though...be...在意思上略有区别：Though...is...是“…虽然…”，Though ...be...是“…即使…”（其实…未必…），如Though he is too weak to walk much, I will advise him to walk a little every day和Though he be too weak to walk much, I will advise him to walk a little every day。
7.It is recommended that the work not be started until all the necessary preparations have been made里的not be不可改作be not。
8.Are you happy? 不可改作Do you be happy? Aren't you happy? 也不可改作Don't you be happy? 比较下面每组里的两句：
- Why aren't you more interested?(你为什么不多关心一点?)
Why don't you be more interested?(你为什么不多关心一点呢 ?[你该多关心一点啊!) - Why aren'r you a tractor driver?(你为什么不是一个拖拉机手?)
Why don't you be a tractor driver?(你为什么不训练做一个拖拉机手呢?)
9.Have you been to see him？是“你去看过他吗？”I have already been to see him是“我已经去看过他了。”
10.was或were后面接不定式完成体表示原来将怎样而不曾怎样。例如：He was to have married her. （他原来将跟她结婚［而不曾实行］。）
