我国对优质食品的认证标准有（）
A.无公害认证
B.绿色食品认证
C.有机食品认证
D.放心食品认证
参考答案：A, B, C
_____ he’s only been learning English for a year, he speaks it very well.
A．Considered
B．Considering
C．Having considered
D．To consider
脚手架拆除时必须遵循什么作业顺序？
