A burning AC motor would be considered what class of fire?()
A. Class "A"
B. Class "B"
Class "C"
D. Class "D"
A vessel is carrying three lights in a vertical line. The highest and lowest of these are red and the middle light is white. Which statement is always TRUE? ()
A. During the day,she would display three balls in a vertical line
B. If making way,she would show masthead lights at night
C. If at anchor,she need not show anchor lights while displaying identifying lights
D. Her fog signal would consist of a rapid ringing of a bell for five seconds every minute
中段回流经过的几层塔盘的板效率一般比较低,因此,我们称这几层塔板为换热板。
A. 正确
B. 错误
气焊在焊接时,保护气氛没有电弧充分,合金元素变为蒸汽而跑掉的较多。
A. 正确
B. 错误