— ________ times a week do you go to the library? — Twice a week.

—Where’s my cat, Bill? —There aren’t any cats here, ___________ there’s a little dog.

Some people waste a lot of food___________ others don’t have enough to eat.

David didn’t give up ______ he had failed in the experiment four times. 

Not only Tony but also Betty ______ to go sightseeing with friends.