finite verb 和 non-finite verb

我们先来看看下面的句子：

1. I am strong. 
2. We are strong.
3. You are strong.
4. He is strong.
5. She is strong.
6. It is strong.
7. They are strong.
8. I eat apples.
9. We eat apples.
10. You eat apples.
11. She eats apples.
12. He eats apples.
13. It eats apples.
14. They eat apples.
15. I am eating apples.
16. We are eating apples.
17. You are eating apples.
18. He is eating apples.
19. She is eating apples.
20. It is eating apples.
21. I have eaten apples.
22. We have eaten apples.
23. You have eaten apples.
24. He has eaten apples.
25. She has eaten apples.
26. It has eaten apples.
27. They have eaten apples.
28. I was strong.
29. We were strong.
30. You were strong.
31. He was strong.
32. She was strong.
33. It was strong.
34. They were strong.
35. I was eating apples.
36. We were eating apples.
37. You were eating apples.
38. He was eating apples.
39. She was eating apples.
40. It was eating apples.
41. They were eating apples.
42. I had eaten apples.
43. We had eaten apples.
44. You had eaten apples.
45. She had eaten apples.
46. He had eaten apples.
47. It had eaten apples.
48. They had eaten apples.
49. I will be strong.
50. We will be strong.
51. You will be strong.
52. She will be strong.
53. He will be strong.
54. It will be strong.
55. They will be strong.
56. I would be strong.
57. We would be strong.
58. He would be strong.
59. She would be strong.
60. It would be strong.
61. They would be strong.

 

上面的这些句子中，有的只有一个 verb, 有的句子有多个 verbs. 其中有一个 verb, 它能告诉我们如下信息：

1. 主语的人称、数， 
2. 整个句子的时间背景

这个 verb，就是 finite verb.

finite verb 是一个英语语法名词.

牛津词典的英文解释是：a finite verb form shows a particular tense, person and number.

新牛津词典的英文解释是：(of a verb form) having a specific tense, number, and person.

韦氏词典的解释是：of, relating to, or being  a verb or verb form that can function as a predicate or as the initial element of one and that is limited(as in tense, person and number).

finite 这个单词，从词源上分析，finite 是源自拉丁语词汇 finire，其基本涵义是"limited in space or time", "to set bounds; come to an end".

牛津词典对 finite 的英文解释是"having a definite limit or fixed size"，也就是“有限的，受限的”。

所以从字面上看，finitefinite verb 就是“受限 verb”. 它的作用是体现句子的时间背景以及主语的人称和数。

所谓体现句子的时间背景，是指该句子所讲述的究竟是过去？还是现在？还是将来？是指这种粗略的时间划分，而不是指明该句子讲述的是哪个具体时间点或时间段。

例如：

1. I ate apples.
2. I eat apples.
3. I will eat apples.

上面例句中加粗且打下划线的斜体字都是 finite verbs. 其中例句 1 讲过去的事情或习惯；例句2 讲现在的事情或习惯；例句 3 讲将来的事情或习惯。

很多情况下，我们只需要知道或者表达事情是发生在过去、还是现在、或者是将来----就够了。我们不需要知道或讲清楚具体的时间点。

如果要讲清楚具体时间，那得搭配时间状语使用。例如：

1. I watched TV last night.
2. I am eating apples right now.
3. I will go to Shenzhen tomorrow. 

当句子中没有时间状语时，我们从 finite verb 就可以判断某件事情或者某个状态究竟是在过去，还是现在，还是将来。这就像汉语中的助词“着、了、过、会”一样，不能告诉我们具体时间，但是能告诉我们大体时间。

再来看 finite verb 体现主语的人称和数这个功能。

例如下面几个句子：

1. I am strong. 
2. We are strong.
3. You are strong.
4. He is strong.
5. She is strong.
6. It is strong.
7. They are strong.

上面这些句子中加粗加下划线的斜体字，之所以形式不一样，是因为主语的人称和数不一样。当主语是第一人称单数时，我们用了 am; 当主语是第二人称时，我们用来 are; 当主语是第三人称单数时，我们用了 is; 当主语是第三人称复数时，我们用了 are. 也就是说 finite verb 在形式上要受到主语的人称和数的限制，要和主语的人称和数保持一致。这就是所谓的 subject verb agreement (主谓一致)

主谓一致原则其实是一条应该被淘汰的冗余功能。汉语语法中就没有谓语要在人称和数上与主语保持一致的规定。英语语法的发展方向是趋向于越来越简单。英语中的主谓一致原则其实也正在简化消失。

我们看下面几个句子：

1. Bill, you are right.
2. Boys, you are right.

可以看到，主语是第二人称是，不管是复数，还是单数，后面的 finite verb 都是 are. 也就是说，这里的 finite verb 已经不需要体现主语的“数”了。

 再看下面几个句子：

1. I will eat apples.
2. We will eat apples.
3. You will eat apples.
4. He will eat apples.
5. She will eat apples.
6. It will eat apples.
7. They will eat apples.

可以看出，will 这个 finite verb, 不管它前面的主语是第一人称、第二人称还是第三人称，也不管主语是单数还是复数，它的形式都是 will，不改变的。也就是说它的形式是不受主语的人称和数的限制的，换句话说，就是它不体现主语的人称和数了。这和汉语是一样的。

再看下面几个句子：

1. I had eaten apples.
2. We had eaten apples.
3. You had eaten apples.
4. She had eaten apples.
5. He had eaten apples.
6. It had eaten apples.
7. They had eaten apples.

可以看出，had 这个 finite verb, 不管它前面的主语是第一人称、第二人称还是第三人称，也不管主语是单数还是复数，它的形式都是 had，不改变的。也就是说它的形式是不受主语的人称和数的限制的，换句话说，就是它不体现主语的人称和数了。

注意一：虽然英语中的主谓一致原则有简化甚至取消的趋势，但是目前还是没有完全简化取消。大家在学习时还是要记住这条规则。

注意二：即使 finite verb 不再体现主语的人称和数了，它还是会体现出整个句子的时间背景的。

综上所述，finite verb 的形式是受到句子的时间背景以及主语的人称和数限制。这也是为什么我们叫它 finite verb 的原因。finite verb 可以翻译为“受限 verb”. 当前我国英语语法书都是把 finite verb 翻译成“谓语动词”，这个翻译并不好，很多学生感到困惑。

我们再来看下面的句子：

1. I am eating apples.
2. We are eating apples.
3. You are eating apples.
4. He is eating apples.
5. She is eating apples.
6. It is eating apples.
7. I was eating apples.
8. We were eating apples.
9. You were eating apples.
10. He was eating apples.
11. She was eating apples.
12. It was eating apples.
13. They were eating apples.
14. I have eaten apples.
15. We have eaten apples.
16. You have eaten apples.
17. He has eaten apples.
18. She has eaten apples.
19. It has eaten apples.
20. They have eaten apples.
21. I had eaten apples.
22. We had eaten apples.
23. You had eaten apples.
24. She had eaten apples.
25. He had eaten apples.
26. It had eaten apples.
27. They had eaten apples.
28. I will be strong.
29. We will be strong.
30. You will be strong.
31. She will be strong.
32. He will be strong.
33. It will be strong.
34. They will be strong.
35. I would be strong.
36. We would be strong.
37. He would be strong.
38. She would be strong.
39. It would be strong.
40. They would be strong.

上面这些句子中的加粗打下划线的斜体字，都是 verbs, 这些 verbs 或者是infinitive, 也就是“不变式”（国内英语语法书基本上都是把 infinitive 翻译成“不定式”，这个翻译不好），或者是后面加-ing 的现在分词(主动分词)，或者是过去分词(被动分词)。这些 verbs 的共同点是，都不反映主语的人称和数，也不反映整个句子的时间背景(过去/现在/将来)。也就是说句子的时间背景以及主语的人称和数，不会限制这些 verbs 的形式。这样的 verbs，我们把它们叫做 non-finite verb, “不受限 verb”. （目前我国英语语法书基本上都是把这类 verbs 叫做“非谓语动词”，这个翻译并不好。）

non-finite verbs 不表达时间背景，但是它们能够表达“状态”和“语态”信息。例如：

1. I am eating apples. 这个句子中的 eating 中的 -ing 告诉我们，吃苹果这个事件是正在持续中。
2. I have eaten apples. 这个句子中的 eaten 告诉我们，吃苹果这个事件已经完成了。
3. I am to eat apples. 这个句子中的 to eat 告诉我们，吃苹果这个事件还没开始。
4. The worker are making toys. 这个句子中的 making 告诉我们两点：第一，做玩具在进行中；第二，工人是 make toys这个动作的 doer（执行者）。
5. Those toys are made in China. 这个句子中的 made 告诉我们两点：第一，这些玩具已经做好了；第二，这些玩具是 make 这个动作的 receiver（承受者、接受者）。