A×-320型直流弧焊机空载电压为()。
A.50~80V
B.220V
C.110V
D.80~100V
参考答案:A
When I met him the other day,it was the first time we________each other since we were at school.[ ]
A.saw
B.had seen
C.were seeing
D.have seen
塑料在加热、加压等条件下具有可塑性,在高温下为柔韧的固体。