"Ago"

[adrianlondon]

Actually, I'm quite comfortable with those; it was the "whole process" description of 过which made me think of those two

[HashiriKata]

My question was just to tease you.

[semantic nuance]

Imagine 2 friends are discussing something they want to eat later after shopping.

A: 你有沒有吃過北平烤鴨?

B: 我沒有吃過. 好吃嗎?

A: 我吃過,還不錯. 你沒有吃過, 那等會兒我們去吃.

2. Then they go to a restaurant where serves that dish. While the waiter is serving the dish, A needs to go to the restroom and asks B to eat first. When A comes back, he askes:

A: 你吃(過)烤鴨了沒? (Did you eat the duck?)

B: 吃(過)了, 吃(過)了. 味道不錯. (Yes, I did. Not bad.)

To be short, 吃過 without 了 stresses the experience you have had. In this example, 我沒有吃過, B's telling that he hasn't had that experience yet. If B has had that experience, he can answer either 我吃過 or 我吃過了. 吃(過)了 in 2 stresses the action of eating duck is done.

Compare the difference below:

A: 你吃過麵嗎? Have you ever had noodles (experience of having noodles so far)

B: 吃過(了) I already have had that experience.

B: 沒吃過. I haven't had that experience yet. (NB: no 了 in negative when talking about experience)

A: 你吃(過)麵了嗎? Did you have noodles? (action)

B: 吃(過)了 Yes, I did. (action is done)

B: 沒吃/or 沒有吃. No, I didn't.

*( )-- optional

Hope it helps.

[HashiriKata]

你有沒有吃過北平烤鴨?

Do people in Taiwan still refer to 北京 as 北平, or does this only occur in 北平烤鴨 ?

[semantic nuance]

we say Beijing 北京, but we often say 北平烤鴨. Nowadays, people say 北京烤鴨, too, just not that often as 北平烤鴨. At least, when I say that, I say 北平烤鴨 without thinking which I should say.

A related question: people here are discussing 了 and 過. they use 'I've studied Chinese 3 years ago." I would like to ask native English speakers if this sentence is grammatically incorrect. As I know, a definite time+ago can only be used in past tense while a definite time +before is used in present perfect tense. Thus, it should be 'I studied Chinese 3 years ago', and 'I've studied Chinese 3 years before'. Anyone to comment on it? Thanks!

[L-F-J]

I think you're right: "I studied Chinese three years ago" and "I've studied Chinese three years before".

The difference is that the first sentence is to tell someone when you studied Chinese. The intention is to let them know the time. The second sentence is to tell someone that you had the experience of studying Chinese three years ago. The intention to share the fact of the experience rather than the time.

[L-F-J]

Can someone explain what the different meanings of the following sentences would be, or if one is incorrect? Thanks! 　

我去过上海几次。

我去过上海几次了。

[stephanhodges]

You could also say "I've studied Chinese, but three years ago."

The "I have studied" is a completed action, and completely in the past. ("studied" is indefinite past, and "have" makes it past completed).

The third time marker in the original sentence, "three years ago", also indicates past, but not completed (it is ambiguous on that point). So, you wouldn't have TWO indefinite past tense indicators in the same sentence.

Adding the "but", however, actually makes it two different clauses. The second clause has an implied "it was", as in "but, it was three years ago".