术前服用阿司匹林的心脏搭桥手术病人应在术前几天停药()
A.2天
B.4天
C.5天
D.7天
E.均不对
参考答案:D
已知两个点电荷相距为r时,它们之间的静电力的大小为F;当这两个点电荷间的距离变为2r时,静电力的大小变为( )
A.2F
B.F2
C.F4
D.F8
My niece has three brothers, all ( ) than she. ( ), John, is an oil worker.
A.older; The oldest
B.older; The eldest
C.elder; The oldest
D.elder; The old one