真题练习

563.Over the past 3 decades the number of students leaving home each year to study abroad _______ at an annual rate of 3.9 percent,from 800,000 in 1975 to 3.5 million in 2008.
A.grew
B.grows
C.have grown
D.has grown
564.Years ago we didn't know this,but recent science _______ that women who drink more than two cups of coffee are more likely to have heart disease than those who don't.
A.showed
B.has shown
C.will show
D.is showing

答案解析
563.答案是D;over/in/during the past 3 decades与完成时连用；the number作主语，谓语用单数，故选D。
564.答案是B;由recent science暗示，此题用现在完成时为妥。