用高级程序设计语言编写的程序称为源程序，它
A. 只能在专门的机器上运行
B. 无需编译和解释，可直接在机器上运行
C. 可读性不好
D. 具有良好的可读性和可移植性
We _______ really late last night, as we were shopping for bargains online.
A. stayed up
B. stay up
C. staying up
D. stays up
It’s a great competition, as there are _______ from all over the world.
A. participated
B. participant
C. participants
D. participate
The two sisters didn’t have much money so they _______ to get their parents a special birthday present.
A. teamed with
B. teamed over
C. teamed in
D. teamed up
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