橡胶软管分为()()软管。
参考答案:高压、低压
He made ________ known to his friends that he didn’t want to enter politics.
A.that
B.it
C.himself
D.him
凝结水常用的过滤形式有()。
A、覆盖过滤
B、磁力过滤
C、微孔过滤
D、粒料过滤