repaired/had repaired

[coelacanth]

Hello there, I try doing some english tests. And here is one of the question:
They ... last month.
1. repaired their house
2. had repaired their house
3. had their house repaired.
The third answer is right. But why can't I say: "They repaired their house last month"? Also there is a marker "last month" in the sentence.
Thanks.

 

[teechar]

The following sentence has a capitalization mistake and appears to be missing tense.

I try doing some english tests.

This one has one mistake.

And here is one of the question:

Can you spot those mistakes and fix them?

 

[coelacanth]

I've tried to do some English tests.
And here is one of the questions.

 

[probus]

In my opinion all three are correct, depending on context.

1. The simple past. You are simply reporting what occurred.

2. The past perfect. You are reporting what occurred before what you are now about to report.

3. While the first two describe what they did themselves, this speaks to what they hired others to do. Still the past perfect tense though.