阅读下面材料在空白处填入适当的内容(1个单词)或括号内单词的正确形式。Theearthistheonlyplanetthatscientistsarecertainhaslife.Whatdoestheearthhavethatotherplanetsinoursolarsystemdon't?

Question

阅读下面材料 在空白处填入适当的 内容(1个单词) 或括号内单词的正确形 式。

      The earth is the only planet that scientists are certain has life. What does the earth have that other planets in our solar system don't? For one thing the earth is just the right temperature. As 61  third planet from the sun

the earth seems to be just the right distance away. The planets that are closer to the sun

are 62 (extreme) hot and their surfaces are baking in the sun. The farthest planets are frozen balls.

     When the earth developed it 63  (cover) by many gases. The gases caused the earth 64. (be)

hot. But something 65. (amaze) happened. The temperature was just right for thick clouds to form. It rained very hard for a long time. This gave the earth its oceans. Water made 66. possible

for plants to grow. Then the plants created oxygen in the atmosphere 67. the gas -that humans and animals breathe.

Mars is the only planet in the solar system that seems to be anything like the earth. It is 68. (small) than the

earth and it is quite a bit cooler. But it is not too cold for humans. The most unexpected sight on Mars is dried-up river beds. However it is believed 69. Mars was once much wetter.Does this mean there could have been living things on Mars? Scientists are not  sure but there 70.(be) no sign so far.

Answer 1

61. the。考查定冠词。由语境可知，third.在此表顺序，故其前应用定冠词the。

62. extremely。考查副词。设空处修饰 形容词hot 故填副词extremely (非常) 。 

63. was covered。考查一般过去时的被 动语态。it (指代the earth) 与cover 之间是被动关系，且此处表示过去的 状态，应用一般过去时的被动语态， 故填 was covered。

64. to be。考查不定式作宾语补足语的 用法。cause sth. to do sth.意为“引起某物做某事”

65. amazing。考查形容词作定语的用 法'。设空处修饰something 故填 amazing (令人吃惊的) 。

66. it。考查it的用法。设空处作形式宾 语，真正的宾语是for plants to grow 故填it。

67. which。考查关系词。设空处引导非 限制性定语从句，指代oxygen且在 从句中作主语，故填which 68. smaller。考查形容词的比较      级。由 than可知，此处应用形容词的比较 级，故填smaller。

69. that。考查连接词。设空处引导主语 从句，又因从句成分及意义均完整， 故填that。

70. has been。考查现在完成时。由so far可知，此处应用现在完成时，故填 has been。