梯形的下底长为8cm,中位线长为6cm,则上底长为( )cm.
4
服用铋剂时的粪便颜色为()
A.鲜红色
B.暗红色
C.白色或灰白色
D.绿色
E.黑色或柏油色
____ you ask many different questions will you acquire all the information you need to know.
A.If only
B.As far as
C.So long as
D.Only if