Problem: How does the sentence end?

Rebecca's skin showed no signs of age, while Christine looked haggard, because
Answer: Christine consumed lots of cigarettes.

Problem: How does the sentence end?

Robert has amazing silky hair unlike Justin because
Answer: Robert takes good care of his hair.

Problem: How does the sentence end?

The new race car will not fit in the garage because the
Answer: car is too tall.

Problem: How does the sentence end?

It was easy for Joel but not Kevin to have fun on the camping trip because
Answer:
Kevin had not learned how to enjoy the outdoors.