问题 问答题

同学们知道:“往热水瓶里灌水,随着瓶中水量的增多,热水瓶中发出声音的音调会越来越高,这是由于瓶里空气柱发生振动所引起的现象.”

(1)对上述现象和原因的描述,你能得出进一步的结论是:______.

(2)把一条均匀的长金属管切成4段,长度各不相同,然后将这4段金属管挂起来,做成一组鸣钟,用槌子敲击这4根管,发出音调最低的是(______)

A.最长的管;        B.最短的管

C.4根管的音调一样; D.要看敲哪一部分

(3)医生在给病人检查腹部是否有积水时,总是用手轻轻地敲击病人的腹部,即“叩诊”,其判断的依据是腹部发出声音的;依据______的信息,可判断病人积水的可能性较大.

答案

(1)往热水瓶中灌水时,水量越多,空气柱越短,振动越快,发出声音的音调越高;

(2)金属管越短,敲击时振动越快,发出声音的音调越高,反之,金属管越长,振动越慢,发出声音的音调越低;

(3)敲击腹部时,腹部有积水和无积水时发出声音的音调不同,故可以通过音调判断病人是否有积水;

故答案为:(1)空气柱越短,振动越快,发出声音的音调越高;

(2)A;

(3)音调.

阅读理解

Most people around the world are right-handed. This also seems to be true in history. In 1799, scientists studied works(作品) of art made at different times from 1, 500 B. C. to the 1950s. Most of the people shown in these works are right-handed, so the scientists guessed that right-handedness has always been common through history. Today, only about 10% to 15% of the world’s population is left-handed.

Why are there more right-handed people than left-handed ones? Scientists now know that a person’s two hands each have their own jobs. For most people, the left hand is used to find things or hold things. The right hand is used to work with things. This is because of the different work of the two sides of the brain (大脑). The right side of the brain, which makes a person’s hands and eyes work together, controls(控制) the left hand. The left-side of the brain, which controls the right hand, is the centre for thinking and doing problems. These findings show that more artists should be left-handed, and studies have found that left-handedness is twice as common among artists than among people in other jobs.

No one really knows what makes a person become right-handed instead of left-handed. Scientists have found that almost 40% of the people become left-handed because their main brain is damaged(损害) when they are born. However, this doesn’t happen to everyone, so scientists guess there must be another reason (原因) why people become left-handed. One idea is that people usually get right-handed from their parents. If a person does not receive the gene (基因) for right-handedness, he/she may become either right-or left-handed according to the chance (偶然性) and the people they work or live with.

Though right-handedness is more common than left-handedness, people no longer think left-handed people are strange or unusual. A long time ago, left-handed children were made to use their right hands like other children, but today they don’t have to.

小题1: After studying works of art made at different times in history, the scientists found       .

A. the art began from 1, 500 B. C.

B. the works of art ended in the 1950s

C. most people shown in the works of art are right-handed

D. most people shown in the works of art are left-handed

小题2: How many people in the world are left-handed now?

A.Less than one sixth.

B.More than a half.

C.About 40%.

D.The passage doesn’t tell us.小题3: What is the left hand for most people used to do?

A.It’s used to find or hold things.

B.It’s used to work with things.

C.It’s used to make a person’s eyes work together.

D.It’s the centre for thinking and doing problems.小题4:  According to (根据) the  passage, which of  the following is NOT true?

A.No one really knows what makes a person become right-handed.

B.Left-handedness is cleverer than right-handedness.

C.Today children are not made to use their right hands only.

D.Scientists think there must be some reason why people become left-handed.小题5:The best title(标题) for this passage is       .

A.Scientists’ New Inventions

B.Left-handed People

C.Which Hand

D.Different Brains, Different Hands.

单项选择题