问题 选择题

2008年春节前,京珠北段韶关段普降大雪,为确保道路的畅通,有关部门向公路上的积雪撒固体氯化钠以使冰雪很快融化.其原因是(  )

A.固体氯化钠溶于水放热

B.氯化钠的水溶液沸点较高

C.氯化钠水溶液结冰的温度比水低

D.固体氯化钠与雪发生化学反应,放热

答案

答案:C

阅读理解

NASA has opened the door to the next generation of space discovery by announcing great plans for a base for humans to live on the surface of the moon forever.

The project to build a base on the moon will begin soon after 2020, with astronauts living there within four years.

The project comes after several excellent scientists and environmentalists asked humans to look beyond Earth to ensure the survival of the species (物种).

Eventually, the moon will be a base for humans to explore the solar system and one day land on Mars.

NASA began planning for the first moon landing since 1972 when George Bush, the US president, announced his new plan for space exploration four years ago.

NASA has already talked about the design of the Orion spacecraft that will replace the old space shuttle fleet in 2010.

The plan for the moon base, however, is the first detailed explanation of how NASA intends to prepare for the first manned exploration of deep space and a possible Mars mission within 30 years.

Scientists also believe that the south pole on the moon contain rich natural gases such as the rare helium-3 that could be used as fuel for the generation of nuclear power. Besides, teams of astronauts living there for six months at a time would mine for hydrogen and oxygen to make water and possibly rocket fuel.

小题1:When was the plan to explore space first announced according to the passage?

A.In 1972.

B.In 1950.

C.In 1968.

D.In 2020.小题2:The reasons why NASA has begun the plan to explore space include the followings except ________.

A.to protect Earth

B.to explore deep space

C.to finish Mars mission

D.to show how powerful the USA is小题3:In the future, when people fly to the moon, they will probably not bring with them too much ________

A.hydrogen

B.food

C.oxygen

D.water小题4:The passage mainly talks about ________.

A.the USA’s new plan for space exploration

B.how to build a base on the moon

C.why to ensure the survival of the species

D.where to get new natural resources

问答题 简答题