单选题

A、 One always knows what his muscles are doing.
B、 One performs simple actions without working.
C、 One"s muscles are used only to the extent necessary for each action they perform.
D、 One improves muscular action consciously.

【正确答案】 C

【答案解析】[听力原文]
Are you aware that you actually possess six senses? The sixth is a muscular sense responsible for directing your muscles intelligently—to the exact extent necessary for each action you perform. For example, when you reach for an object, the sensory nerves linking the muscles to the brain stop your hand at the correct spot. This automatic perception of the position of your muscles in relation to the object is your muscular sense in action.
Muscles are stringy bundles of fibers varying from one five-thousandth of an inch to about three inches. They have three unique characteristics: they can become shorter and thicker; they can stretch; and they can retract to their original position.
More than half of a person"s body is composed of muscle fibers, most of which are involuntary—in other words, work without conscious direction. Women have only 60 to 70 percent as much muscle as men for their body mass. That is why an average woman can"t lift as much, throw as far, or hit as hard as an average man.

What does intelligent use of the muscles mean?

[解析] 文中指出to the exact extent necessary for each action you perform，可知C项符合。to the extent某种程度。

A、 Voluntary muscles.
B、 Involuntary muscles.
C、 Muscles fibers.
D、 Sensory nerves.

【正确答案】 C

【答案解析】[听力原文]
What is composed of more than half of a person"s body?

[解析] 由“More than half of a person"s body is composed of muscle fibers”可知C为正确答案。

A、 Because she has more voluntary muscles than an average man.
B、 Because she has only 60 to 70 percent as much muscle for her body mass as man"s.
C、 Because she has 60 to 70 percent less muscles for her body mass.
D、 Because she has less muscle fiber for her body weight.

【正确答案】 B

【答案解析】[听力原文]
Why is an average woman weaker than an average man?

[解析] 由“Women have only 60 to 70 percent as much muscle as men for their body mass. ”可知B为正确答案。

A、 The efficiency of our muscles.
B、 The normal breathing function.
C、 Direction our muscles intelligently.
D、 The work of only our involuntary muscles.

【正确答案】 C

【答案解析】[听力原文]
According to the selection, what is the muscular sense responsible for?

[解析] 由“The sixth is a muscular sense responsible for directing your muscles intelligently”可知C为正确答案。

A、 They can become shorter and thicker.
B、 They can stretch.
C、 They have sense linking the muscles to the brain.
D、 They can retract to their original position.

【正确答案】 C

【答案解析】[听力原文]
Which of the following is NOT the unique characteristic?

[解析] 从“They have three unique characteristics: they can become shorter and thicker; they can stretch; and they can retract to their original position. ”可知C不是肌肉的特性。