单项选择题

When we speak，sound waves begin to travel and go in a11 directions（）

A．当人们说话时，声音向四面八方传开。
B．当我们说话时，声音就开始传播，并且向四面八方传开。
C．当我们说话时，声波开始传递，而且向四面八方传播。
D．当我们说话时，声波就开始传播，并且走向四面八方。

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单项选择题

A．become a permanent student in the U. S. A
B．take up a summer course in the U. S. A
C．go to enjoy a tourist's in the U. S. A
D．spend a summer traveling in the U. S. A

单项选择题

If you go to the U. S. A, you'll be able to make friends with those（）

A．outside the place where you study
B．outside the United States
C．who will ask you to stay longer in the U. S. A
D．who will continue to keep in touch with you after you return to your own country