问题 填空题

声音在15℃的空气中的传播速度是______m/s.放鞭炮时用手捂住双耳,这是在______处减弱噪声的;在城市街道禁鸣喇叭,这是在______处减弱噪声;植树造林,增加绿地面积,不仅可以打造绿色生态环境,而且还可以在______减弱噪声.

答案

(1)声音是由物体振动产生的,声音在15℃空气中的传播速度大约340m/s;

(2)放鞭炮时用手捂住双耳,这是在人耳处减弱噪声的;在城市街道禁鸣喇叭,这是在声源处减弱噪声;植树造林,增加绿地面积,可以在传播过程中减弱噪声.

故答案为:340;人耳;声源;传播过程中.

选择题
完形填空

At the beginning of this century, medical scientists made an interesting discovery: we are built not just of flesh(肌肉) and blood but also of time. They were   21  to show that we all have a ‘body clock’   22  us, which controls the   23  and fall of our body energies,   24  us different from one day to the next.

The   25  of a ‘body clock’ should not be too   26  since the lives of most living things are controlled   27  the 24-hour night-and-day cycle(循环). We feel   28  and fall asleep at night and become  29  and energetic during the day. If the 24-hour cycle is   30  most people experience unpleasant   31 . For example, people who are not   32  to working at night can find that   33  of sleep causes them to   34  badly at work.

  35  the daily cycle of sleeping and   36 , we also have other cycles which   37  longer than one day. Most of us would   38  that we feel good on some days and not so good on  39 ; sometimes our ideas seem to flow and at other times, they   40  do not exist.

小题1:  

A.anxious

B.careful

C.able

D.proud小题2:  

A.around

B.inside

C.between

D.on小题3:  

A.rise

B.supply

C.use

D.movement小题4:

A.showing

B.treating

C.changing

D.making小题5:

A.idea

B.opinion

C.story

D.invention小题6:

A.difficult

B.exciting

C.interesting

D.surprising小题7:

A.from

B.over

C.by

D.during小题8:

A.dull

B.dreamy

C.tired

D.peaceful小题9:

A.regular

B.excited

C.clear

D.lively小题10:

A.shortened

B.disturbed

C.reset

D.troubled小题11:

A.moments

B.senses

C.feelings

D.effects小题12:

A.used

B.allowed

C.expected

D.prevented小题13:

A.miss

B.none

C.need

D.lack小题14:

A.show

B.perform

C.manage

D.control小题15:

A.With

B.Except

C.As well as

D.Rather than小题16:

A.waking

B.moving

C.living

D.working小题17:

A.repeat

B.remain

C.happen

D.last小题18:

A.believe

B.agree

C.realize

D.allow小题19:

A.others

B.the other

C.all other

D.other小题20:

A.only

B.just

C.still

D.yet