[Q]: How does the sentence end?

The excavator was abandoned and they brought in a crane to build the house, because the

[A]: excavator proved useless to the process.

[Q]: How does the sentence end?

Tanya went to get some focus study group advice from Lindsey because

[A]: Tanya needed some help.

[Q]: How does the sentence end?

Eric forgot to change the oil in their motor but Craig didn't.

[A]:
Eric had a lot of engine problems.