Experiments _______ that children can be instructed in swimming at a very early age, as early as about two months.
A.are proving B.will be proved C.are proved D.have proved
Because of the progress he ______ in his performance, he was soon promoted to project manager.
A.had made B.had been made C.makes D.has been making
The man was so surprised at _______ that he did not try to escape or defend himself.
A.discovered B.discovering C.to be discovered D.being discovered
It is estimated that the number of tourists who travel abroad ______ in the past decade.
A.have doubled B.have been double
C.have been doubled D.has doubled
I ______ her to the party but I didn’t get her phone number.
A.had planned to invite B.have planned to invite
C.planned to invite D.was planning to have invited
I guess your failure in the exam ______ inadequate preparation.
A.results in B.results from C.caused by D.causes
