Joe has been in the army for two years.

[Alice Chu]

1. Joe has been in the army for two years.
This sentence means that Joe joined the army two years ago, and he is still in the army.

Are the two sentences below correct?
2. Joe has joined the army for two years.
3. Joe has been joining the army for two years.

 

[Rover_KE]

No. :-(

Joe joined the army two years ago.

 

[5jj]

2. Joe has joined the army for two years.

That would mean that he has enlisted for a period of two years.