雅思基础语法练习Complete the following sentences by circling the missing words.1.Science still a cure for cancer.a.doesn’t find c.hasn’t foundb.haven’t found d.aren’t finding2.While he a route to the Indies, Columbus discovered America.a.searched c.had searched forb.was discovering d.was searching for3.Existing reserves of fossil fuel by 2045.a.have been run out c.is going to be run outb.will have run out d.have run out4.If logging of tropical rainforests continues at the present rate, a 30 per centincrease in atmospheric CO2 by the year 2000.a.there will be c.there would beb.there might have been d.there could not have been5.Only by investing heavily in value-added exports from the present tradeimbalance.a.the country can emerge c.can the country emergeb.the country might emerge d.the country emerged6.The mystery of the double helix , the scope for genetic engineeringdramatically increased.a.having solved c.solvingb.having been solved d.solved7.Since the mid-’60s considerable research in embryo transplants .a.has carried out c.has been carried outb.was done d.was carried out8. several hypotheses have been advanced for the disappearance of the dinosaur,no conclusive evidence supports any of them.a.despite c.althoughb.in spite of d.in spite of the fact9.Until the 16th century the earth to be flat.a.is believed c.believedb.has been believed d.was believed10.If the temperature of the reactor 500C higher meltdown would have occurred.a.was c.was beingb.had been d.had11. adequate precautions are take, there is no risk involved in the operation.a.Although c.Neverthelessb.Providing d.EvenMy supervisor advised me to the problem.12.a.look ahead c.look out ofb.look down d.look intoThe more acid you add to the solution, it becomes.13.a.cloudier c.the cloudiestb.the cloudier d.more cloudyThe lecturer said ‘It’s time you the literature review.’14.a.began c.should beginb.begin d.are beginning15After studying our experimental results, the tutor suggested the experiment. . to repeat c.we repeatb.that we to repeat d.me to repeatAfter your results you should make an appointment with your tutor.16.a.you receiving c.you have receivedb.you would have received d.you received17You the experiment twice, not once..a.should have carried out c.haven’t carried outb.shouldn’t have carried out d.couldn’t have carried out18It looks you’ve made a mistake..a.as c.ifb.as though d.perhapsAfter receiving her results, the student stopped .19.a.to worry c.worryingb.having worried d.to be worried20.You include this section. It is not necessarya.must c.don’t needb.couldn’t d.don’t have to21.Unless an extension at least one week before the due date, it will notbe given.a.you request c.you requestedb.you will request d.requesting22.The assignment made me .a.to think hard c.think hardb.thinking hard d.thought hardThe scientists were prohibited the danger zone.23.a.to enter c.enterb.entering d.from enteringthe right answer I would have got full marks.24.a.Had I known c.If I’ll knowb.if I would have known d.If I was knowingThe results were convincing that we decided to publish them.25.a.so c.veryb.such d.so muchway you do it, the answer is always the same.26.a.However c.Who everb.whichever d.Why everproducing methane, the process also produces carbon monoxide.27.a.Apart c.Besidesb.As well d.In additionThe biologist admitted excessive numbers of animals in laboratory tests.28.ing c.being usedb.to use edA whale is a mammal, it is warm-blooded and gives milk to its young.29.a.who c.which means thatb.which d.that30.He appears minor problems.a.to have had c.was havingb.having d.hadGrammar Practice Answer1.C11.B21.a2. d 12.D22.c3.B13.B23.d4.A14.A24.a5.C15.C25.a6.A16.C26.b7.C17.A27.c8.C18.B28.a9.D19.C29.c10.B20.D30.a。