posted by rfvv today at 6:08pm

1. He runs 50 meters in 9 seconds.
2. He runs 50 meters durng 9 seconds.
[Can we use #2?]

3. He finished the project in 5 days.
4. He finished the project during 5 days.
5. He finished the proj\ect during the 5 days.
[Are they all the same? Which ones are correct?]
Writeacher today at 6:35pm
#2 is not used. #1 is the usual way to express this idea.

#3, 4, and 5 all mean about the same thing, but 4 and 5 are not normally used expressions.
==================================
Thank you for your help.
1-1. He runs 50 meters for 9 seconds.
3-1. He finished the project for 5 days.
[What about 'for' instead of 'in'? Can we use 'for' in each sentence?]

1-1 and 3-1 are both incorrect. The preposition "for" does not work in either of those sentences.

Yes, you can use 'for' instead of 'in' in both sentences:

1-1. He runs 50 meters for 9 seconds.
3-1. He finished the project for 5 days.

Using 'for' in these sentences implies a duration of time. It suggests that he runs 50 meters continuously for a duration of 9 seconds and that he worked on the project continuously for a duration of 5 days. 'In' can also be used in these sentences to express the same idea, but 'for' is more commonly used in this context.