Question

Can somebody help me with the middle part thank you.

Answer 1

The answer you would be looking for is 2,3,6. As the other sentences are either too long without a comma, or they do not have the proper make-up to be full sentences. Number 4 is a good example, as whatever is moving down the hill is unknown. That is why it is not a complete sentence.

Answer 2

I THINK it is 2,3,5 and 6 that are complete sentences.