（ ）6.________at his model plane over the weekend，he didn’t complete it.
A.As he worked hard
B.Hard as he worked
C.How he worked hard
D.How hard he worked
（ ）7.His hands _______ a little as he took up a pen and began to write.
（ ）8.I have four letters to write today and I have finished_________.
（ ）9.I remember _______ her at the party last week.
D.to have met
（ ）10.If the weather is fine，We shall go Oil playing basketball________.
（ ）11.I wonder_______ we could have a talk after the meeting,
（ ）12.When We reached the station the train had not arrived yet;so we_______.
A.needn't have hurried
B.didn’t need to hurry
C.need not to hurry
D.had not needed to hurry
（ ）13.What the monitor said at the class meeting ________ quite all right.
（ ）14.Hold on，please.I'll put you________ to the manager.
（ ）15.People were disturbed and began to see where the noise_______.
（ ）16.“Where is Wu Dong?”“He_______ Shanghai.”
A.has gone to
（ ）17.The room ________often cleaned by the students.
（ ）18.Be careful next time;——？
（ ）19.I looked and looked，and at last I made out two figures moving slowly in the _______.
（ ）20.Would you like a piece of cake_______your eoffee?
We do not know how the first fire was 21 .Early fires on the earth were certainly caused by nature，not by Man，some were caused by lightning in a storm;22 ，perhaps，by the hot material which came out of a volcano.Quite possibly，at times，the heat of the sun set light 23 some dry grass or leaves.At first Man，like other animals，was probably afraid of fire. 24 great was the power of fire that he feared it and worshipped it.Gradually，however，with his better power of thinking，he overcame his fear.Probablly he overcame most of his fear when he 25 how to make fire for himself.Throughout the ages he has learned more about fire，how to control it，and how to use it 26 many ways.Now fire is no longer a master of a god;it is a 27 .
We call only guess how 28 first learned that a fire was useful and what uses he made of it.By 29 a burning stick from fire which had been started naturally，he could make afire at his own“home”。He could keep the fire burning by adding more dry grass.1eaves and wood.The‰30 the chief purpose of frightening animals away.He discovered，by some accident，that flesh roasted in front of a fire 31 better.Then he found that roasted flesh would keep longer，without going bad， 32 uncooked flesh.It must have been much later that Man learned to cook food by heating it with 33 water or with steam.He could not use such methods 34 he had learned how to make pots 35 holding water.