一件商品打“七二折”出售，比原价便宜了28%．______．
打“七二折”出售，就是按原价的72%出售，比原价便宜了：
1-72%=28%；
故答案为：正确．
I can’t understand it is that makes him so difficult at school.
A．how
B．what
C．why
D．which
干燥器排泄阀在得电时作用如何？（绘图说明）
