《供电营业规则》规定，供电企业应在用电营业场所公告办理各项用电业务的（）、（）和（）。
参考答案：程序；制度；收费标准
下列计算正确的是（ ）
A．3m+3n=6mn
B．y3÷y3=y
C．a2•a3=a6
D．（x3）2=x6
Mike has put on so much weight this year that his mother has to________all his trousers to his measure. [ ]
A. let out
B. give away
C. bring in
D. lay out
