8．My father and mother are my ．( )A．parentsB．parentC．friendD．teacher——青夏教育精英家教网—

	A．	We are new here．		B．	You are welcome，too．
	C．	Thank you．		D．	Good idea．

2．My name's Lingling，__________ am a Chinese student．（　　）

A．

B．

She

C．

D．

1．The mother traveled for many hours to return home to talk to her childrenin person（亲自）

20．You probably don‘t think about soil often，but the following report may help you learn about science of soil．
What is soil made of？
Soil is made of sediments （沉积物） and humus（腐殖质）．Sediment is small pieces of rock broken down over time by rain，ice，and wind．Sediment is often found in water．Humus comes from decayed（腐烂的） plants and animals．It helps give plants a lot of the food they need to grow．
How does soil form？
Over centuries，rock breaks down into very small pieces．
The rock pieces mix with humus．
The humus gets thicker and thicker over time．Soil is formed（形成）l
How are soils different？
Soils can be different colors and have different textures（质感）．Texture is how the surface of an object feels．Color and texture are two features（特征） of soil．
Plants and soil
Plants do not grow well in some soils．Sandy soi1 is too dry．It does not hold water．Soil with too much clay is too thick．Most plants grow well in dark，rich garden soil that has different sediments and a lot of humus in it．

The title （标题）：（81）Science　of　soil
The things in soil	Sediment is often found in water． Humus （82）comes　from decayed plants and animals．
The steps of forming	Rock breaks down into very small pieces． The rock pieces mix with humus． The humus gets （83）thicker　and　thicker．
（84）The　differences　between　soils	Soils can be different colors and have different textures．
The relationship between plants and soil	（85）Dark，rich　garden　soil is good for plants to grow in．

19．

It happens every spring．Flowers come out everywhere on the same day．But how do plants"know"when to flower？
For years，it has been a difficult question for scientists．But a US research group may have finally answered it-the secret lies in a protein（蛋白质）called FKF1．This helps plants to know when the days become long and when they get short．Then they can tell the seasons are changing．
Researchers found the FKF1protein when they were studying a plant called Arabidopsis（拟南芥）．It is sensitive（敏感的）to sunlight，and can be made active by sunlight．
Plants produce this protein every day in the late afternoon all year．If there is no light at this time，for example in winter when the sun goes down early，the protein won't be active．But when spring comes and the days get longer，the FKF1protein can be made active by day light and the plants"know"it is time to flower．"If there is light in the late afternoon，plants will know that the days are getting longer and that it is the best time for flowers to come out，"explained Takato Imaizumi，leader of study．But when conditions are poor for growing，such as during autumn or winter when the weather is cold and days are short，plants won't flower．
Although researchers have only studied how the FKF1protein works in the Arabidopsis，they believe that it is the same with many other plants，including crops such as rice and wheat．This could be useful to the agricultural industry．
"If we can control when flowers come out，we might be able to increase crop production，"Imaizumi said．

38．The passage is mainly aboutA．
A．how plants"know"when to flower
B．what people can do with plants
C．how seasons are changing
D．what kind of plant Arabidopsis is
39．Scientists found the FKF1protein when they wereD．
A．answering a question
B．controlling the clours of flowers
C．planting flowers in the garden
D．studying a plant called Arabidopsis
40．The best time for flowers to come out is whenB．
A．it rains in spring
B．there is light in the late afternoon
C．it is getting dark
D．the sun goes down early
41．Scientists believe thatA．
A．other plants also know when to flowers
B．flowers are more valuable than fruits and vegetables
C．people have known how to control when flowers come out
D．if the weather is cold and days are short，plants will flower．

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