问题 填空题

请你根据所学的知识,回答下列问题:光在同种______介质中沿直线传播;在探究凸透镜成像的规律的实验中,在光屏上出现的烛焰的像______实像(选填“不一定是”或“都是”);当你走近竖立的平面镜时,你通过平面镜所成像的大小______(选填“变大”、“变小”或“不变”);光能在真空传播,声音______(选填“能”或“不能”)在真空中传播.

答案

①光在同种均匀介质中沿直线传播,光在不均匀的介质中不沿直线传播;

②因为实像可以在光屏上承接,而虚像则不能,所以在光屏上出现的烛焰的像都是实像;

③平面镜成的像与物是等大的,故像的大小取决于物体自身的大小,与物体离平面镜的远近都无关,故不管你走近竖立的平面镜还是远离平面镜时,你通过平面镜所成像的大小不变.

④声音的传播需要介质,可以在固体、液体和气体中进行传播声音,但在真空中不能传播声音.

故答案为:均匀;都是;不变;不能.

阅读理解

Do you want to know something about chil­dren in Africa? What to they do for fun every day? Find out here:

Education

School is expensive for many African children. Lots of families can’t afford school uniforms or ex­ercise books even though they don’t have to pay for school.

For those lucky enough to go to school , they have a lot to learn. Some take two language clas­ses: English or French, and their first language. There is also math, science, history, social studies and geography. Chores take up much of children’s time after school. They have to get water and fire­wood for the family every day. Also there’s clean­ing , washing and helping Mum with the meal.

Daily fun

It’s not all work and no play. Sports are very popular. Children can make goals with twigs ( 嫩树枝)and their own footballs with plastic and bits of string ( 绳子 ). They play in the country and the streets of old towns. There’re many football teams for teenagers in Africa.

Internet

It’s really expensive to get on the Internet. To surf the net for 20 hours costs over 600 yuan. This is more than the average (平均的) monthly pay per person.

Egypt and South Africa are the top two users of the Internet in Africa. All of the capital cities there can get on the Internet.

Some schools offer computer lessons but few students can enjoy computer fun at home.

小题1: The underlined word "Chores" probably means

A.网上冲浪

B.家务杂活

C.体育活动

D.家庭作业小题2: Sports are very popular in Africa because chil­dren _________.

A.do not need money to play

B.can play all kinds of ball games

C.don’t like to go to school

D.don’t like to do their homework小题3:The passage is mainly about_________.

A.education in Africa

B.children’s school life in Africa

C.the Internet in Africa

D.children’s daily life in Africa小题4:From the passage, we can infer (推断) that in Africa_________.

A.basketball is popular among children

B.children in Africa have to pay for school

C.some children in Africa have to take two for­eign language classes

D.people in Egypt and South Africa may get higher pay than people in the other countries

单项选择题