在地面上以速率v1竖直向上抛出一个物体,物体落地时的速率为v2,若物体所受空气阻力的大小与其速率成正比,则物体在空中运动的时间()
A.
B.
C.
D.
参考答案:A
. They are teachers and don't realize the basic/primary rules and principles _____ to start and run a company.
A.in which
B.for whom
C.with which
D.of whom
在下列的系谱图中,哪个肯定是常染色体隐性遗传病的系谱图()
A.A
B.B
C.C
D.D