切花采收后的保鲜处理技术包括（）
A、预处理浸泡
B、低温贮藏
C、人工催开
D、售后瓶插
参考答案：A, B, C, D
-Turn off the TV, Jack.___________ your homework now?
-Mum, just ten more minutes, please. [ ]
A. Should you be doing
B. Shouldn't you be doing
C. Couldn't you be doing
D. Will you be doing
广州市环城高速公路新的编号为：（）
A、S80
B、S81
C、S82
D、S83
