We ____ each other since childhood.
A.have known B.knew C.know D.are knowing
I regret that I waited in the queue for a long time to buy the ticket this morning. I ______ it online.
A.could buy B.must buy
C.could have bought D.must have bought
I ran all the way to the post office, only ___ that it had closed.
A.finding B.having found C.to find D.to be found
I had just finished my test paper ___ the bell rang, announcing the exam was over.
A.unless B.when C.because D.though
Miss Liu is an excellent doctor and she believes her ____ in life is to help the sick.
A.attempt B.attitude C.demand D.mission
Mike gave me a lovely kitty and told me that it required ___ carefully.
A.being looked after B.looked after C.looking after D.to look after
