2.speed up

　　3.be located

　　4.be allowed to

　　5.according to

　　6.contribute to

　　7.derive from

　　8.continue doing

　　9.in the face of

　　10.continue doing

　　11.stop sb. from doing sth。

　　12.cut down

　　13.turn a blind eye

　　14.pay off

　　15.regard…as

　　16.make a living

　　17.be worth doing

　　18.make…into…

　　19.on the spot

　　20. in addition to

　　text b life in the tundra

　　短语表达

　　1.be known as

　　china is known as one of the four ancient civilizations。

　　she is known as a great singer。

　　2.adapt to

　　it is hard for him to adapt to the food and climate there。

　　he is well adapted to the harsh environment。

　　3.threat to

　　heart diseases are major threats to life。

　　darkness is a threat to him。

　　4.to some degree

　　i agree with you to some degree。

　　to some degree he hated his work。

　　5.as if by magic

　　his face turned green as if by magic。

　　the sun appeared after the rain as if by magic。

　　6.give birth to

　　mrs. brown gave birth to a baby girl last week。

　　the summer sun gives birth to many species of arctic plants。

　　7.in search of

　　the whole family was out in search of the lost pet dog。

　　all his life he has been in search of the meaning of life。

　　8.migrate to

　　many birds migrate to the south in winter。

　　he migrated from canada to the united states when he was 30。

　　9.in turn

　　we drove to the beach last week. the two of us took the wheel in turn。

　　theory is based on practice and in turn serves practice。

　　10.result in

　　his carelessness resulted in the accident。

　　deforestation will result in disastrous ecological changes。