[单项选择]When we speak, sound waves begin to travel and go in all 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. 当说话时，声波就开始旅行，并且走向四面八方。

[单项选择]When we speak, sound waves begin to travel and go in all 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. 当说话时，声波就开始旅行，并且走向四面八方。

[单项选择]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。

[单项选择]Be sure to ______ your wife when we go to the party this evening.
A. get
B. bring
C. carry
D. take

[单项选择]Sound waves reflected from a hill can be used to estimate______.
A. height of the hill
B. speed of sound
C. distance of the hill
D. intensity of sound

[填空题]The moon is a very silent world, for sound waves can only travel through the air（）.

[单项选择]Under proper conditions, sound waves will be {{U}}reflected{{/U}} from the hillside or other such obstruction.
A. mirrored
B. bounced back
C. absorbed
D. soaked through

[单项选择](Sound waves) travel (in the air) in much (the same) way (like) water waves spread on the water.
A. Sound waves
B. in the air
C. the same
D. like

[单项选择]According to the passage, when we decide to go for it, we only consider______.
A. safety
B. action
C. result
D. situation

[单项选择] We feel we are happiest when we __ and exchange ideas with one another.
A. chart
B. chatter
C. chase
D. chat

[单项选择]When we encounter more difficulties, we should be more spirited, and we should be more courageous______.
A. the more danger we are in
B. the more in danger we are
C. we are in more danger
D. we are in danger more

[单项选择]When we make friends, we might consider the other person's age because ______.
A. it is not easy to stay friends with someone who shows a clear difference in maturity
B. the degree of friendship between two people and the reason for their shared interest can vary greatly
C. friends need to know all these things
D. this is the most important factor to making friends

[单项选择]

When we think about happiness, we usually think of something extraordinary, a peak of great delight--and those peaks seem to get rarer the older we get.
For a child, happiness has a magical quality. I remember making hide-outs in newly cut hay, playing cops and robbers in the woods, getting a speaking part in the school play. Of course, kids also experience lows, but their delight at such peaks of pleasure as winning a race or getting a new bike is unreserved.
For teenagers, or people under twenty, the concept of happiness changes. Suddenly it’ s conditional on such things as excitement, love, and popularity. I can still feel the agony of not being invited to a party that almost everyone else was going to. But I also recall the great happiness of being invited at another event to dance with a very handsome young man.
In adulthood the things that bring great joy--birth, love, marriage--also bring responsibility and the risk of loss. Love may not last,
A. material gains
B. social distinction
C. spiritual satisfaction
D. academic achievements