Problem: How does the sentence end?

The water in the sink would not go down the drain, because the 
Answer: drain was clogged.

Problem: How does the sentence end?

Angela is choosing a skin toner and needs an advice from Monica, because 
Answer: Monica has a lot of experience.

Problem: How does the sentence end?

Steven was more interested in planning his vacation than Justin because 
Answer: Justin had never wanted to travel.

Problem: How does the sentence end?

Michael was able to climb the apple tree much more quickly than Brian, because 
Answer:
Brian was not very agile or athletic.