作用在同一物体上的两个共点力F1=5N、F2=4N，则它们合力大小可能是 [ ]
A．0
B．5N
C．9N
D．10N
BC
The reason_______ his being late for school was______ he missed the train.
A．for because
B．why that
C．why because
D．for that
A．2t
B．2kg
C．2mg
D．200g
