How Do I Use 完?

[AlexanderH]

Hey all --

So I got this sentence in my Chinese text, and since I don't have class for a few days I am dying to figure out what it means.

我姐姐上个星期过生日，蛋糕没吃完。 Last week it was my older sister's birthday, but I didn't finish eating the cake?

I recall my teacher vaguely mentioning a few examples:

做完功课

吃完

写完

喝完咖啡

So I gathered it probably means " to finish ". I finished my homework. I finished eating. I finishing writing. I finishing drinking coffee.

So you don't need 了? And it is placed after the verb?

Thank you

[natra]

I think that the subject for who ate the cake is sort of ambiguous, but one would not usually assume that it was your sister who was eating it by herself as your translation suggests.

了 here would denote that the action of eating the cake had been finished (by whomever). The action was not finished, so 了 should not be used here.

[AlexanderH]

Please don't quote when it's obvious what you're referring to.

Woops, it's from a much larger dialogue, so the subject has already been established.

Am I correct in the usage though?

[889]

It often means finished off: 蛋糕没吃完 there was still some birthday cake left, 喝完咖啡 the coffee cup was emptied.

[anonymoose]

完 can actually have two meanings in this kind of sentence.

Take the sentence 我吃完饭了 for example.

This could be interpreted to mean either

"I've finished eating the food / I've eaten all the food (and there's none left)"

or

"I've finished eating the food (I'm full up, and can't eat any more of it)"

Which interpretation is correct is usually clear from the context, though there is a possibility of ambiguity.