Usage/meaning of 了(le) in sentence with the word "to-be"?

Question

I know that when you are saying that something is a noun, you use 是 (shì), but when do you use 了(le)? Is it used when you are saying that an action is being completed or that someone or something is doing something?

Answer 1

Basically, 了 is used in one of two ways:

1. Placed after a verb or adjective (to indicate completion), usually identified as 了1.

2. Placed at the end of a sentence, or a phrase, usually identified as 了2.

I suppose your question is about 了2, let's compare a few sentences that with and without 了 at the ends - to indicate a change of state, or a condition, with respect to sometimes in the past:

• 他是(一個)大學生 - He is a college student.

• 他是(一個)大學生了 - He is a college student now/already. (He wasn't the last time you saw him.)

• 這房子是我的 - This house is mine.

• 這房子是我的了 - This house is mine now. (It wasn't before.)

• 明天是星期六 - Tomorrow is Saturady.

• 明天是星期六了 - Tomorrow is Saturaday already. (Express the feeling about time changes with a sigh or an expectation.)

You certainly shall search the web to find more instructions on the uses of 了1 and 了2. Have fun :)

Answer 2

I have never used 了 (le) to mean "to be" in my daily life, and I can't even think of an example where it would work in that context. I haven't seen this usage in any dictionaries either. Where did you come across the idea of 了 meaning "to be"?

Answer 3

Quote:- "When should I use the character 了 to say what something is? I know that in the case of saying that something or someone is a noun, you use 是 (shì), but when is 了 (le) used?"

My answer is based on the assumption that I understand correctly your question or rather the underlying query.

Let's breakdown your question:-

1. "I know that in the case of saying that something or someone is a noun, you use 是 (shì)"

Correct. For example, "He is a good person", "他是一个好人"

2. "...but when is 了 (le) used?"

了 is used when the subject, (He), "became" a good person, i.e. used as a past tense marker.

So, we have, "He is a good person", "他是一个好人", turning into "He became a good person", "他成为了一个好人"

3. "When should I use the character 了 to say what something is?"

Now, is this why you ask about the usage of 了 to mean "to be"?, because "to be" is when "something is", or, something maintaining a contemporaneous form or quality.

I don't think it works that way, as other commentators have also opined.

If I have misunderstood your question, then of course my answer is wrong.