— Could I have an interview with Mr Green now, please?
— Sorry, he _________ a meeting. You'd better wait a minute.
A:has
B:had
C:is having
D:was having
下图反映了
人体内氧气与血红蛋白分离的场所是( )
如图所示,绕过定滑轮的轻绳拴在小车上,另一端吊一物体,若小车沿水平向前匀速运动,则物体的运动状态为( )