丨-2丨=( ) A.2 B.-2 C.±2 D.-丨2丨

题型:选择题

问题:

丨-2丨=(  )

A.2

B.-2

C.±2

D.-丨2丨

考点:绝对值
题型:选择题
若函数f(x)=3cos(ωx+θ)对任意的x都有f(
π
6
+x)=f(
π
6
-x),则f(
π
6
)等于 ______
题型:选择题

阅读理解。

     The incident took place on Sunday,the 25th Of June. On that particular day,a south wind had been

gusting (劲吹) on and off all morning. It was not strong enough to cause us any concern,so we carried

on our daily work not suspecting what was about to happen.

     The storm gave us very little warming. Black clouds loomed over the distant horizon (地平线) so

suddenly that we were taken by surprise. Even then,we were not really worried,as the clouds seemed

to be moving over our house and towards the distant mountains. Then,just as the clouds had moved

inland,the wind suddenly swung around in a full circle and we were facing a major storm.

     Instantly,we were busily preparing for the worst. The whole family had experienced such a storm

before and everyone remembered the damage it had caused to stock and crops. There was very little we

could do about the corps. But we needed to protect the animals in case the river flooded again. My older

brother called his sheep-dog and began driving our small flock of sheep to higher ground above river. If

the river flooded,they should be safe there.

     In the meantime,my father was mending a shed roof that had partly fallen down after many years of

fine service. If the tin flew off,it could damage the house. My younger brother began hurriedly carrying

firewood under the shelter. My job was to help Mum board up the windows.If the storm develop into a

cyclone (旋风), the boards would protect the glass.

     The storm raged for four hours,pouring more rain on us than we had seen in the last five years. As

expected. the river broke its banks and came slowly up towards the house and the stock. '

     Then, just as we were beginning to lose hope,the storm stopped as suddenly as it had begun. The

animals were safe, and the roof was still nailed on. "All's well that ends well," Said my mother.

1. When the black clouds appeared suddenly in the distance _____.

A. the family were surprised

B. they were extremely worried

C. they were preparing for the worst

D. they faced the storm bravely

2. "There was very little we could do about the crops" indicates that _____.

A. little damage would be done to the crops

B. they had everything ready for the crops

C. they felt unable to protect the crops

D. the crops should be safe enough there

3. The underlined word "stock" in the third paragraph refers to _____.

A. money owned by the family

B. goods for sale

C. supplies for family use

D. farm animals .

4. It can be inferred from what the mother said that _____·

A. they had no damage at all

B. everything went beyond their expectation

C. everything was under control

D. the family could have suffered a greater loss

题型:选择题

对磁介质进行报废处理,()是应采用的最安全措施。

A.直接丢弃

B.砸碎丢弃

C.集中保管

D.专用强磁工具清除

题型:选择题

献血者有下列哪种情况不能判定为暂缓献血()。

A.妇女月经期前后三天

B.近五年内输注全血或血液成分者

C.分娩未满一年者

D.感冒病愈未满一周者

E.肺结核未满一年者

题型:选择题

激光具有亮度高、方向性强、()等特性。

A.抗干扰性强

B.单色性好

C.单色性差

D.相干性好

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