把相邻的两名同学看做一个整体,9个中选1个,有9种选法;
故选:B.
我国的舟山渔场每年都有一段时间的“休渔期”,其主要原因是( )。
A.鱼类每年有一个集中的产卵期
B.舟山渔场附近海域污染越来越严重,以至于鱼量越来越少
C.那段时期沿海地区台风活动频繁,为渔民安全考虑,因此不让他们出海捕鱼
D.舟山因捕鱼过量,致使目前已无鱼可捕
To find the cause of a gasoline engine’s failure to start,you should().
A.Break the joint in the fuel line at the engine and let the gas run in the bilges
B.Disconnect the wires at the spark plugs and make the spark jump the gap
C.Prime the engine with ether through spark plug openings
D.Ventilate the space,then check the battery,spark plugs,carburetor,and fuel line