若3x=7y,那么x和y成______比例.
因为3x=7y,所以xy=73(一定),是x、y的比值一定,所以x、y成正比例.
故答案为:正.
---- Your daughter has won the first prize in the contest .What a smart girl she is !
--- .______________ .
A It’s nice of you to say so B .She was really lucky
C . No one else could do it D . Oh ,not really
国家对哪些企业实行安全生产许可证制度?