如何理解球会员工的需求

太阳直射点南北移动的原因是（    ）

A．地球的公转

B．地球的自转

C．太阳的运动　

D．地球公转运动和相对不变的地轴倾角

设立外商投资旅行社，对外国旅游经营者要求其年旅游经营总额为( )。

A．400万元人民币

B．4000万元人民币

C．4000万美元

D．4000万美元以上

阅读理解。

     The year is 2094. It has been announced that a comet(彗星) is heading towards the

earth. Most of it will miss our planet, but two pieces will probably hit the southern half

of the earth.

     On 17 July, a piece four kilometers wide enters the earth's atmosphere(大气层) with a

massive explosion. About half of the piece is destroyed, but the remaining part hits the

South Atlantic at 200 times the speed of sound. The sea boils and a huge hole is made in

the sea bed. Huge waves are created and spread outwards from the hole. The wall of water,

a kilometer high, rushes towards southern Africa at 800 kilometers an hour. Cities on the

African coast are totally destroyed and millions of people are drowned.

     Before the waves reach South America, the second piece of the comet lands in

Argentina. Earthquakes and volcanoes are set off in the Andes Mountains. The shock

waves move north into Califomia and all around the Pacific Ocean. The cities of Los

Angeles, San Francisco and Tokyo are completely destroyed by earthquakes. Millions

of people in the southern half of the earth are already dead, but the north won't escape

for long. Because of the explosions, the sun is hidden by clouds of dust, temperatures

around the world fall to almost zero.Crops are ruined. The sun won't be seen again for

many years. Wars break out as countries fight for food. A year later, no more than 10

million people remain alive.

     Could it really happen? In fact, it has already happened more than once in the history

of the Earth. The dinosaurs were on the Earth for over 160 million years. Then 65 million

years ago they suddenly disappeared. Many scientists believe that the Earth was hit by

a piece of object in space. The dinosaurs couldn't live through the cold climate that

followed and died out. Will we meet the same end?

1. What is mainly described in the passage?______

A. A historic discovery.

B. An event of imagination.

C. A research on space.

D. A scientific adventure.

2. When the first piece hits the South Atlantic, it causes.______

A. an earthquake

B. damages to cities

C. an Earth explosion

D. huge waves

3. Why can't the northern half of the Earth escape for long?______

A. Because the land is covered with water.

B. Because the light and heat from the sun can not reach the earth.

C. Because people there can not live at the temperature of zero.

D. Because wars break out among countries.

4. By giving the example of dinosaurs, the author tries to prove .______

A. animals could not live in the cold climate

B.what happened 65 million years ago was an invented story

C. the human beings will die out in 2094

D. the Earth could be hit by other objects in space

采用双重化配置的两套保护装置宜安装在各自保护柜内，并应充分考虑（）和（）时的安全性。

某单层广房柱，在基础顶面作用有荷载F=300kN，M=87kN·m，V=5kN，基础梁传来F′=180kN，柱截面b₂×a₂=400mm×600mm，基础底部面积I×b=3m×1.8m，基础变阶处尺寸，长a_z1=1150mm，宽b_z1=950mm，基础高度H=850mm，其余尺寸见题图。基础埋深d=1.2m，混凝土强度等级C20，f_t=1.1N/mm²，HPB235钢筋，f_y=210N/mm²。

下台阶的冲切面积与（）项值接近。

A．0.659m²

B．0.723m²

C．0.765m²

D．0.812m²