发声体单位时间内振动的次数叫______,它决定了声源发出声音的______.

题型:填空题

问题:

发声体单位时间内振动的次数叫______,它决定了声源发出声音的______.

考点:音调与频率的关系
题型:填空题

阅读理解。

      Peter wanted very much to be a soldier when he was a child. So he joined the army (军队) when

he was eighteen, and for several months he was taught how to be a good soldier. He did quite well in

everything except shooting. One day he and his friends were practicing their shooting (射击), and all

of them were doing quite well except Peter. After he had shot at the target (靶) nine times and hadn't

hit it once, the officer who was trying to teach the young soldiers to shoot said, "You are quite hopeless,

Peter. I don't waste your last bullet! Go behind that wall and shoot yourself with it!"

       Peter felt ashamed (难为情). He went behind the wall and a few seconds later, the officer and the

other soldiers heard the sound of a shot.

       "Oh, dear!" the officer said. "Has that silly man really shot himself?" He ran behind the wall as quickly

as he could, but Peter was all right."I'm sorry, sir," he said, "but I missed again."

1. Peter joined the army in order to ______?

A. be a soldier

B. be good at shooting

C. make friends

D. get a good job

2. The officer thought Peter was hopeless because ______.

A. he didn't know how to use a gun.

B. he didn't get along well with other soldier.

C. he was poor at shooting.

D. he couldn't do anything well.

3. What the officer said at the end of the first paragraph(段落) shows that ______.

A. the officer really wanted Peter to die

B. the officer was very angry with Peter

C. the officer was not a kind-hearted man

D. the officer was afraid that Peter would shoot himself

4. The officer felt ______ when he heard the sound of a shot.

A. ashamed

B. frightened

C. excited

D. disappointed (失望)

5. What happened at the end of the story?

A. Peter became a good soldier.

B. Peter killed himself behind the wall.

C. The officer was pleased with Peter in the end.

D. Peter missed the target for the tenth time.

题型:填空题

一工件以孔定位,套在心轴上加工与孔有同轴度要求的外圆。孔的上偏差是+0.06,下偏差是0,心轴的上偏差-0.01,下偏差是-0.03。其基准移位误差()

A、0.09

B、0.03

C、0.045

D、0.025

题型:填空题

患者,男性,30岁,近几日突感口腔内多处“牙床”胀痛不适,晨起口中有血腥味。检查;有腐败性口臭,牙龈广泛充血水肿,上、下前牙龈缘如虫蚀状,覆灰白色坏死假膜。

下列与本病发生无关的是()。

A.存在已久的慢性龈炎或牙周炎

B.心身因素

C.营养不良或消耗性疾病

D.吸烟

E.遗传因素

题型:填空题

实验室数据修约时拟舍去的数字最左一位为5,而后面有并非全为零数字,修约时说法正确的是()。

A.保留末位数为0则舍去

B.保留末位数为奇数才能进一

C.可以直接进一

D.保留末位数为偶数才能进一

题型:填空题

对乙肝病毒感染有保护作用的是()

A.抗HBe

B.抗HBs

C.DNA聚合酶

D.抗核抗体

E.抗HBc

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