Problem: How does the sentence end?

Jeffrey taught yoga and hoped Donald would drop out as a student because 
Answer: Donald was disruptive.

Problem: How does the sentence end?

The man tried to put the boat in the pool but the 
Answer: boat was too large.

Problem: How does the sentence end?

Emily would smile in all the photographs but not Christine because 
Answer: Christine had crooked teeth.

Problem: How does the sentence end?

So 
Answer:
Leslie plays video games because Leslie has a lot of free time while Nelson has to work all the time.