Unit 20 Archaeology教案
b. only imitate the first washing machine
c. power the first ever-made washing machine by electricity
d. have to wait for the first spin-drier for a long time
9. the word“crude”in the sentence“but it was crude by today’s standards”probably means __________ .
a. useless b. ugly-looking c. rough d. not skillfully made
10. the article mainly tells us about __________ .
a. the great inventors in the world
b. the important inventions in the world
c. the short history of household machines
d. the importance of the machines used in
c
we know that many animals do not stay in one place. birds, fish and other animals move from one place to another at a certain time. they move for different reasons: most of them move to find food more easily, but others move to get away from places that are too crowded.
when cold weather comes, many birds move to warmer places to find food. some fishes give birth in warm water and move to cold water to feed. the most famous migration（遷移）is probably the migration of the fish, which is called“salmon”. this fish is born in fresh water but it travels many miles to salt water. there it spends its life. when it is old, it returns to its birthplace in fresh water. then it gives birth and dies there. in northern europe, there is a kind of mouse. then it gives birth and dies there.