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                            This is a piece of very important news. You must have it ____ to your country at once
                        
                     
          
    
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                            ______ it is you ve found, you must give it back to the owner of it.A.WhicheverB.WhatC.Wha
                        
                     
          
    
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                            When once you have had the disease, you are______ to it for the rest of your life.A.immune
                        
                     
          
    
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                            It was very kind of you to do the washing up yesterday, but you______it.A.mustn"tB.wouldn"
                        
                     
          
    
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                            Once environmental damage_____, it takes hundreds of years for the system to recover.A.has
                        
                     
          
    
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                            Once you _____ the knack of it  you will have no further difficulty.A.shall haveB.had h
                        
                     
          
    
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                            — What do you think of the maths problem? — It’s very easy and most of us have______.