He is on (a) one-month sick leave.

[sitifan]

https://dictionary.cambridge.org/zht/詞典/英語/sick-leave
1. He is on one-month sick leave.
2. He is on a one-month sick leave.
Which of the above sentences is correct?

 

[Rover_KE]

1 is possible, but 2 is better.

Also He's on a month's sick leave.

 

[emsr2d2]

Or "He's on sick leave for a month" or "He's off sick for a month".

 

[sitifan]

1 is possible, but 2 is better.
Also He's on a month's sick leave.

Are the sentences below acceptable?
3. He's on two-month sick leave.
4. He's on a two-month sick leave.
5. He's on two months' sick leave.

 

[emsr2d2]

3 is incorrect. (In my opinion, 1 was incorrect too, in post #1.)

 

[teechar]

1. He is on one-month sick leave.

That one is wrong. You can, for example, say:
He is on a/one month's sick leave.
He's on two months' sick leave.

However, it's more straightforward to use emsr2d2's suggestions in post #3.