信誉度即对产品的信任程度和社会影响程度(声誉)。( )
参考答案：对
Only after spending several nights working on the math problem to wonder whether the problem was wrongly set.
A．had he begun
B．he began
C．did he begin
D．began he
一条大鲨鱼，尾长是身长的一半，头长是尾长的一半。已知头长3米，这条大鲨鱼全长多少米( )
A．20米
B．21米
C．22米
D．23米
