sentence: Rachel would suffer from cramps every month on their period but Sarah wouldn't. 
complete: Sarah had to go to the store to buy some cough medicine.

sentence: At the end of the semester, Derrick took a vacation to the Bahamas while Hunter didn't, so 
complete: Hunter was bored.

sentence: Leslie's plays are better produced than Derrick's even though 
complete:
Derrick has been in the business longer.