依据灾害类型可将灭火救援预案划分为（）类。
A、4
B、5
C、6
D、7
参考答案：C
The lecture given by Professor Johnson on the Antarctic is very attractive, and at the beginning, it is _____ asking us questions about the mysterious continent.[ ]
A. in fact
B. in advance
C. in the form of
D. actually
仓单，是指交割仓库开具并经期货交易所认定的标准化提货凭证。（）
