关于一达通服务费的收取,以下说法正确的是?()
A.对普通会员收取固定服务年费
B.无门槛,不收取服务费用
C.服务费收取退税款的4%
D.只对出口通会员实行免费服务
参考答案:C
Plastic bags won’t be allowed to be used for free in the supermarkets. They can’t _________ easily, which does great harm to our environment.
A.break off
B.break in
C.break down
D.break out
满足哪些条件才算升温钝化开始?