下述的各种功能中，______不是操作系统的功能。 A．对文件和作业进行管 B．对

国家公务员辞职后两年内到与原国家行政机关有隶属关系的企业和营利性事业单位工作的（）。

A.无须任何机关批准

B.须经原任命机关批准

C.须经原任命机关的上一级机关批准

D.一律由当地政府批准

学术会议正在举行分组会议，某一组有8人出席，分组会 * * 问大家原来各自认识与否。结果是全组中仅有一个人认识小组中的三个人，有三个人认识小组中的两个人，有四个人认识小组中的一个人。若以上统计是真实的，则最能得出以下哪项结论

A．会议 * * 认识小组的人最多，其他人相互认识的少。

B．此类学术会议是第一次召开，大家都是生面孔。

C．有些成员所说的认识可能仅是在电视上或报告会上见过而已。

D．虽然会议成员原来的熟人不多，但原来认识的都是至交。

The volcano is one of the most surprising frightening things of nature. Maybe you have seen pic­tures of these " fireworks " of nature. Sometimes when a volcano erupts, a very large wall of melted rock moves down the side of a mountain. It looks like a " river of fire". Sometimes volcanoes ex­plode, throwing the melted rock and ashes high into the air. But where does this melted rock come from?

The earth is made up of many layers (层). The top layer that we see is called the crust. Under the crust are many layers of hard rock. But far, far beneath the crust the rock is so hot that it is soft. In some places it even melts. The melted rock is called magma. Sometimes the magma breaks out to the surface through cracks (裂缝) in the crust. These cracks are volcanoes.

Most people think of mountains when they think of volcanoes. But not every mountain is a volca­no. A volcano is simply the opening in the earth from which the magma escapes. The hot magma, or lava as it is called, cools and builds up on the surface of the earth. Over thousands of years, this pile of cooled lava can grow to be very, very big. For example, the highest mountain in Africa, Kilimanja­ro, is a volcano. It rises more than 16,000 feet above the ground around it.

8. The underlined word "erupts" means ______.

A. moves down   B. breaks away    C. builds up       D. suddenly throws out lava

9. Which words in the passage have the same meaning as "melted rock"?

A. volcano and crust                B. crust and hard rock

C. magma and lava                D. volcano and magma

10. Which is the correct order of the layers of the earth (beginning with the top layer)?

A. crust — hard rock — magma — soft rock

B. crust — hard rock — soft rock — magma

C. agma — soft rock — hard rock — crust

D. volcano — cracks — magma — crust

11. The best title of the passage should be______.

A. The Volcano        B. Kilimanjaro Volcano   C. The Mountains   D. The Melted Rock

如图所示，重为12N的物体A放在足够长的水平桌面上，通过轻质细绳与滑轮相连，不计绳与滑轮间的摩擦及动滑轮重。重为6N的物体B通过滑轮拉动物体A向右作匀速直线运动。一段时间后，物体B接触地面，A继续向右运动的过程中，物体A受到的摩擦力为          N，物体A的动能将         （选填“变大”、“不变”或“变小”）。

输血可以引起的感染有（）

A.梅毒

B.丙型肝炎

C.弓形体病

D.艾滋病

E.巨细胞病毒感染