问题 选择题

关于地球自转速度的叙述正确的是(   )

A.就线速度而言,青藏高原小于南极;就角速度而言,青藏高原大于南极

B.青藏高原与马里亚纳海沟的角速度相等

C.南北极点线速度为0,但角速度最大

D.纬度越低,线速度越小

答案

答案:B

题目分析:本题考查地球运动。地球自转角速度规律:除极点外,处处相等;线速度:自赤道向两极递减。故本小题选B,青藏高原与马里亚纳海沟的角速度相等,都为15度每小时。

点评:本题解题的关键是掌握地球自转速度的变化规律,知识性试题。地球自转角速度规律:除南北两极外,自转角速度处处相等;自转线速度规律:自赤道向两极递减,两极点的角速度和线速度都为0。

单项选择题 A1型题
阅读理解

   Life on land probably began about 430 million years ago, though it has stayed in the water for perhaps as much as 3,000 million years. When we think of the first thing on land, we probably think of strange animals coming out of the oceans, but in fact no animals could have been living if plants had not been on land first. Plants had to be on land before animals arrived. They supplied the first land animals with the surrounding and food necessity, since then, the plants, are the only form of life that is able to get and store energy.

  The first plants to stay out of the water were probably certain kinds of algae(海藻)which were followed by other plants that grew close to the ground and needed water in which to reproduce. Once the move to land had been made, however, evolution(进化)happened quickly. By the end of 100 million years, plants had developed their roots(根), and some had got tree -like forms since height was very important in gaining sunlight. About 300 million years ago, much of the world was covered with forests of huge trees. In most ways they were like modern trees. They had roots, leaves, wood, but mostly they had not developed seeds.

59.The main idea of the first paragraph is ________.

  A. life on land probably began 430 years ago

  B. the first animal on land came from oceans

  C. there wouldn't have been animals without plants

  D. plants are the only form of life that is able to get and store energy

60.Which of the following statements is true according to the passage?

  A. Algae probably has stayed for more than 430 million years.

  B. It is impossible that algae might be the earliest plant on land.

  C. Plants get food from animals in the oceans.

  D. Evolution began after animals appeared on land.

61.Plants with roots appeared about ________ million years ago.

  A. 430     B. 300      C. 330      D. 100

62.According to the passage, ________ appeared earlier than ________.

  A. apples; oranges         B. oranges; apples

  C. oranges; roses         D. algae; wheat