The heart is believed to _____blood into veins(血管) which are netted all over the body, thus keeping a person alive.
The police were seeking more information to find out ______ the rich merchant.
Not until he called the secretary three times ______ that the manager went to an important meeting.
---- You don’t go to that supermarket quite often, do you? ---- No, I only go there ______ because it’s too far away from my house.
During the reconstruction of the city, many modern tall buildings went up ______ old shabby houses were torn down.
---- Can you hand in your composition tomorrow? ---- Sure. ______ it handed in on time, I’ll stay up tonight.