1 阅读材料,回答问题.
在地球仪上,连接南北两极的半圆弧,叫经线.经线指示南北方向.与南北极距离相等的大圆圈,叫赤道.所有与赤道平行的圆圈,叫纬线.纬线指示东西方向.纬线在南北两极缩成一点.
(1) 纬线之间是否平行?为什么?
(2) 经线之间是否平行?为什么?
(3) 如果两条纬线的纬度差为$10°$,它们的距离是多少?(假设地球半径为6371千米,$π$取两位小数)

(1) 纬线之间是平行的,因为它们都与赤道平行.
(2) 经线之间不平行,因为它们都在两极相交.
(3) 约为1111.39千米.

1 Complete the sentences with the given words in their proper forms.(用括号中所给单词的适当形式完成下列句子)
(1) The scientists (study) the changes of the Earth's climate last year.
(2) Look! The workers (plant) trees to make the Earth more beautiful.
(3) Yesterday, we (learn) a lot about the Earth in science class.
(4) The factory (not stop) polluting the river until the government took action last month.
(5) At present, many people (try) their best to protect the Earth's environment.

(1) studied
(2) are planting
(3) learned
(4) didn't stop
(5) are trying

2 Choose the best answer and complete the passage.(选择最恰当的选项完成短文)
The ground rumbles(隆隆作响). Hot liquid, ash(灰), and rocks shoot out of the mountain top. The (1) is filled with smoke. These are the sights and sounds of an erupting volcano(火山).
A volcano is a type of mountain. The mountain has an opening at the top. It allows hot liquid to (2) from the Earth's crust(地壳).
There are different types of volcanoes. Some are active. They can erupt(喷发)at any time. Others are sleeping. They haven't erupted for many years. Volcanologists are scientists who study volcanoes. They (3) when an eruption will happen. Volcanologists use measuring instruments to check on a volcano's rumblings. They can warn people of eruptions. Volcanologists can save lives.
Volcanoes can be (4). When one is ready to erupt, people must be sent to safe places. But there are advantages of these flaming(燃烧的)mountains. They create new (5). The Hawaiian Islands were formed by eruptions.
Volcanoes can also benefit the planet. When a volcano explodes, it releases dust. This can block sunlight and help cool the planet. And a volcano's ash can be (6) for plants. It adds minerals(矿物质)to soil. Did you know that people can use volcanic heat as a source of energy? The energy powers things in a natural way.
() (1) A. liquid B. ash C. air D. rock
() (2) A. stop B. escape C. protect D. fly
() (3) A. predict B. help C. know D. change
() (4) A. beautiful B. delicious C. gentle D. dangerous
() (5) A. life B. land C. air D. water
() (6) A. harmful B. natural C. friendly D. healthy

(1) C
(2) B
(3) A
(4) D
(5) B
(6) D