如图所示,弹簧测力计和细线的重力及一切摩擦不计,物重G=2N,则弹簧测力计A和B的示数分别为( )
A:2N,0
B:0,2N
C:2N,4N
D:2N,2N
9+9+9+9+9=5×9.
I saw him in the library yesterday. He ________ a book at that moment.