Problem: How does the sentence end?

My shampoo did not lather easily on my Afro hair because the 
Answer: hair is too dirty.

Problem: How does the sentence end?

It was easier to calculate the taxes for the diner than for the store because the 
Answer: store was a bigger business.

Problem: How does the sentence end?

Following the advice from the chef, Mary used a wooden cutting board to cut meat instead of a plastic cutting board, even though the 
Answer: wooden cutting board is porous.

Problem: How does the sentence end?

Joel had to borrow dish liquid from Kyle because 
Answer:
Joel had went to the store when they were out.