During the last three decades, the number of people participating in physical fitness programs ______ sharply. A was increasing B. has increased C. had increased D. will be increasing 答案:B。考查动词时态。根据句首的during the last three decades这个时间状语,可以判断出后面句子应该用 现在完成时态。 【句意】过去三十年来,参加体育锻炼的人数增长了。下列各组条件中,能判定四边形ABCD为矩形的是( )
A.ÐA=ÐB=90° B.AB∥CD,AD=BC,AC=BD
C.AB∥CD,AB=CD,AC=BD D.AC=BD,ÐA=90°