Question

1. Let's break up the wall.
2. Let's break the wall.
(What is the difference between the two sentence?)

3. He wanted to get some rest.
4. He wanted to take some rest.
(Are both OK?

5. He got rest after working hard.
6. He took a rest after wroking hard.
(Do we have to use 'a' or not in both sentences? Thank you!)

Answer 1

1. - means you will break it into pieces (usually so you can haul away all the debris).

2. - means you will break it, but not necessarily demolish it.

3 and 4 are fine, yes.

6 is better than 5 -- and yes, because of "a" in front of "rest." (Check the spelling of "work" in 6.)