When should 了 be after the verb and when should it be at the end of the sentence?

Question

In a sentence such as "因为我去面试了，所以我刮了胡子", in one case, 了 is after the sentence, while in the other case it's after the verb, even though in both cases, 了 is used to express the past tense.

So how to know where to put 了? Is there any rule to follow?

Answer 1

In my opinion, you can use "了" right after the verb or at the end of the sentence when "了" is used to show the past tense. However, in your case, that's another thing that I want to clarify.

I think, "去面试" should be treated as one phrasal verb, something like the phrasal verb "go fishing", "go shopping" in English.Here "面试" (interview) is a noun which has a verbal meaning, and thus I will treat "去面试“ as one verb, rather than treat “面试” as the object of the verb "去".If you say "我去了北京", it's different because here "北京" is the object of "去“. Treating the two words as one verb, of course you should not insert “了” inside it.

I would say :

因为我去面试了，所以我刮了胡子. or 因为我去面试了，所以我刮胡子了.

I would also say:

因为我去参加(参加=participate in)了面试，所以我刮了胡子.

Here, “去参加” is treated as one verb and “面试" is its object.

or

因为我去参加面试了，所以我刮了胡子.

Answer 2

了 usually means you've done something. In most cases it can be put either after the verb or noun in the sentence and makes no difference. But

For example below sentence is equivalent to the sentence in this question.

因为我去了面试，所以我刮了)胡子。
yīn wéi wǒ qù le miàn shì，suǒ yǐ wǒ guā le hú zi。

Answer 3

Paraphrasing from http://www.douban.com/group/topic/11223733/:

1. “了”常常用在句末，说的是已经发生的情况(了 is usually placed at the end of a sentence to indicate something already happened). ... 在有“来、去、到“等组成的连动句中，”了“应该放在第二个动词或句子之后(In phrasal verbs with 来、去、到, 了 should be placed after the second verb or at the end of the sentence. This is exactly what @Huang's answer said).

2. 表示动作的结束“了”一般用在动词后面(了 is usually placed after a verb to indicate the action is finished).

The examples in question are excellent demonstration of these rules. 面试 is a (hopefully) long event, and it's preceded by 去, so you put 了 at the end. In comparison, 刮胡子 is a shorter action so you put 了 after the verb 刮.