They have rebuilt his house and it looks nice now.

[Alice Chu]

Are the following sentences correct?
1. They have rebuilt his house and it looks nice now.
2. They rebuilt his house and it looks nice now.

 

[5jj]

Both are grammatically possible.

 

[Alice Chu]

Both are grammatically possible.

(1) Please tell me the difference between the two sentences above.

(2) Is the sentence below correct?
1. They had rebuilt his house and it looks nice now.

 

[tedmc]

(1) Please tell me the difference between the two sentences above.

(2) Is the sentence below correct?
1. They had rebuilt his house and it looks nice now.

The present perfect tense is used for a completed action which is relevant to the present. Thus, the first sentence sounds more natural.
The second sentence seems to suggest that there are two unrelated facts.

The past perfect tense is inappropriate.

 

[Tarheel]

(2) Is the sentence below correct?
1. They had rebuilt his house and it looks nice now.

No. In fact, it's rather jarring.

There is a way to use that phrase. (See below.)

They had just rebuilt his house, and then it was destroyed by a tornado.