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

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