单项选择题
How long warning must be provided by the CO2 warning Mann before CO2 is discharged into a space （）.
A.5 seconds B.10 seconds C.15 seconds D.20 seconds
单项选择题 Which statement regarding garbage disposal is correct?（）
单项选择题 The sections of an Oil Record Book proceeding the log pages contain a （）.
单项选择题 If an incorrect entry were made in the Oil Record Book, you should （）.
