2．I had just finished my work my friend came to visit me．( )A．whileB．whenC．asD．if——青夏教育精英家教网——

2．I had just finished my work ______ my friend came to visit me．（　　）

1．Across countryside，non-food crops are growing alongside wheat．Some are used in new alternatives to plastics and other materials，but others will simply be burned．
Burning crops is becoming more popular because it is good for the planet．Doing so is also cheaper than burning fossil fuels．As more land is devoted to non-food crop production，the economics of crops for fuel are likely to become even more favorable．
Humans have been burning such biomass-organic materials from plants or animals-since they discovered fire．But that burning fossil fuels could have catastrophic consequences has brought biomass back into fashion．
Even allowing for emissions（排放） of carbon dioxide from fuel used in planting，harvesting，processing and transporting biomass fuel，replacing fossil fuel with biomass can typically reduce greenhouse gas emissions by more than 90per cent．
Power stations around the world are experimenting with forms of biomass to add to their coal or oil，with encouraging results．Indeed，power companies could profit by turning to biomass，especially when the subsidies（补助） many governments offer for using renewable energy are taken into account．
Farmers can benefit from growing biomass．In Europe，the reduction of subsidies for certain crops is exposing farmers to market forces．Instead of being paid for whatever they produce，farmers must seek a clear demand for their product．Many believe that the demand for alternatives to fossil fuels could be just such a driver．
But while biomass offers a variety of potential alternatives，the world's infrastructure（基础设施） has developed around burning fossil fuels to such a stage that switching to biomass involves a change in conception that many companies have not accepted．
Also，there are problems with using biomass．Although most coal-fired power stations could take a small amount of their fuel from biomass without significant adjustment，few are built to run on biomass alone．Burning some forms of biomass also causes environmental problems．Oils and waste can be smelly，while wood produces smoke unless burned properly．
The supply chains for fossil fuels are set up well，but those for biomass are just the beginning．Sources of supply for biomass rely on farm production and can therefore be less reliable．They are necessarily limited and it wouldn't make sense to turn a very large amount of valuable agricultural land away from food crops．But as the world adjusts to the need to control greenhouse gas emissions，these problems may receive more attention．

67．What do we know about biomass？C
A．It is a useful way of burning crops．
B．It is a new alternative to be used widely．
C．It is plant and animal matter used to provide power．
D．It is a popular approach to fighting against pollution．
68．What are the advantages of using biomass？D
a．It gives off less greenhouse gases．
b．It helps farmers receive subsidies for what they produce．
c．It has met the clear demand for energy．
d．It has brought subsidies for some power companies．
e．It is cheaper than burning fossil fuels．
A．a，b，c B．b，c，d C．c，d，e D．d，e，a
69．For coal-fired power stations，C．
A．more effective ways to use biomass have been tried
B．using renewable energy has become their daily task
C．burning biomass alone would require considerable changes
D．setting up dependable supply channels needs governments'support
70．What is the author's attitude towards biomass fuels？A
A．Objective．B．Sceptical．C．Disapproving．D．Defensive．

16．An Interesting Festival
The Agricultural Feast takes place after the Independence Day．It is not a worldwide  （61）celebration （celebrate）．Only Christians in Mexico look forward to its arrival for its religious origin．
Long ago，humans'ancestors were bad．They fooled and  （62）played （play） tricks on each other and never kept their word．So God turned up  （63）and drowned all their crops．Humans starved day and night，weeping．In order to gain God's forgiveness，a woman poet set off to see God．She admired God and kept apologizing．God was  （64）moved （move）．With his permission，humans finally had good harvests again．So，（65）to wipe （wipe） sadness and remind themselves  （66）of the belief in God，people began the festival．
On the festival，people gather in open air，such as playgrounds or parking lots，and energetically have fun with each other all night long，as though they were never tired．（67）When a beauty dressed up in lovely clothing reads poems in memory of the poet，everyone holds their breath．Then，（68）it is the custom that the bones of a rooster head is given to her as an award．
（69）Obviously （obvious），the story is not true，but  （70）the festival is interesting．

15．Peter bought a map as soon as he got to Los Angeles ______ he lost his way there．（　　）

14．Cooperative learning allows us to have more chances to acquire ______ is beneficial to ourselves．（　　）

13．Research on brain activity shows imagination is generated in the right side of the brain； ______，the left side of the brain is thought to be"logical"．（　　）

12．Actually（事实上），on second thoughts，I don't think I am for your proposal．

11．It can take many years tostruggle（奋斗）for a high paid job nowadays．

10．We all hope those who aresuffering（遭受） from this disaster will be safe．

9．Theobvious（显而易见的）way of reducing pollution is to use cars less．

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