Problem: How does the sentence end?

Mary used a box instead of an envelope to send a sweater she made because shipping within the 
Answer: envelope is expensive.

Problem: How does the sentence end?

We like to dance the tango more than the waltz since the 
Answer: tango is more fun.

Problem: How does the sentence end?

The date at the diner lasted longer than the one at the restaurant because the 
Answer: restaurant closed earlier.

Problem: How does the sentence end?

I had a more difficult time at the Police Academy than at school because the 
Answer:
academy was tougher.