which sentence is better ?

[liuchunsheng123456]

the two sentences like these :
While I was doing my homework I felt hungry.1)
When i was doing my homework i felt hungry . 2)

i don't think the sentence 2 is right , is it ? if the sentence 2 isn't right , could you tell me why ?

[Pete]

the two sentences like these :
While I was doing my homework I felt hungry.1)
When i was doing my homework i felt hungry . 2)

i don't think the sentence 2 is right , is it ? if the sentence 2 isn't right , could you tell me why ?
Both are possible, but you use them in slightly different ways. The first (with while) emphasizes the duration of the time that you were doing your homework, and says that you felt hungry during that period.

The second (with when) considers the time when you were doing your homework as one particular part of the day and says that at that time you felt hungry.

They both describe the same specific occurrence, but the viewpoint and emphasis are different in the two sentences.

We tend to think of "when" as standing for a point in time and "while" as standing for a period of time. Someone who says the second form is wrong thinks that because the time of doing homework is clearly a period, not a point, "when" cannot be used. I personally think that many times someone will consider such a period as also being an "extended point" in comparison to a much longer period, and so will use "when" quite naturally.

[liuchunsheng123456]

Thank you very much for your reply .
Could you take a look at these two sentenses ?

While i was writing letters last night , he was watching TV.
" While " here can be replaced by" When "? i wondered it quite a time and hope to get your help .

[Pete]

Thank you very much for your reply .
Could you take a look at these two sentenses ?

While i was writing letters last night , he was watching TV.
" While " here can be replaced by" When "? i wondered it quite a time and hope to get your help .
The same distinction applies here. Most likely, the speaker meant "while". The emphasis is on the extended period during which you were writing letters. We think of both the writing letters and the watching television as taking place over the same block of time.

If you switched to "when", the emphasis would be that during the course of the evening you did a number of different things; one of those things was write letters. Your friend ("he") also did a number of different things last night. The time that you were writing letters is the time that he was watching TV.

Again, both forms actually describe the same happening, but the emphasis is different. My feeling is that the "while" statement would be much more likely. The "when" statement is more specific; it would probably come in answer to a particular question like, "When was he watching TV last night?"

{Oh, one thing I noticed in your question is a problem with spacing and quotation marks. Do not put a space between a quotation mark and the quoted material that is between the paired quotation marks.}

[liuchunsheng123456]

many many thanks to your wonderful reply .