Unit 4 Wildlife Protection reading课时作业

　　Ⅰ.单词拼写

　　1．Darwin believed that we (进化)from apes.

　　2．I (附加)a copy of my notes for your information.

　　3．Since I'm here，I'd like to try a (有代表性的) dish of this country.

　　4．The dying fire was throwing out a (阴暗的) red light.

　　5．Don't grasp at the (脆弱的) branch，or you may break it.

　　6．The window frames have (腐烂)away completely.

　　7．There are some (甲虫)on the plants.

　　8．The flower has seven (花瓣)．

　　9．The air was (芬芳的)with scents from the sea and the hills.

　　10．The meat gives out an unpleasant (气味)．

　　【答案】　1.evolved　2.attach　3.typical　4.dull　5.delicate　6.rotted　7.beetles　8.petals

　　9.fragrant　10.odour

　　Ⅱ.阅读理解

　　A

　　Have you ever wondered why stems(茎)grow upwards and roots downwards? Why plants always seem to turn towards the light and climbing plants run up rather than down? The answer is simple: auxin(植物生长素)，a chemical substance that controls growth in plants.

　　Auxin gives away its secrets

Auxin is a plant hormone(激素)．Darwin was already interested in it in the 19th century.Only in recent years，however，has the hormone started to give away its secrets，thanks to intensive molecular research.Auxin is produced in the young，growing parts of plants and then transported throughout the plant-to a low­lying stem for example.The stem needs to straighten out as soon as possible to be able to absorb the topside，resulting in the underside growing faster and the stem straightening out.For the same reason，plants in front of windows will always turn to the light.This active regulation of auxin transport allows plants to take ideal advantage