About half an hour before the engine is required, cooling water at （） must be circulated.

[主观题]a half hour and made sure that the girl was all 84

[试题]a half hour and made sure that the girl was all __________84

[主观题]It took him half an hour to do his homework．（改为同义句）H．e__________ half an hour__________ his homework．

[主观题]Tina sat under the tree half an hour ago．（用now改写）Tina ________,________under the tree now．

[问答题]About half of the fruit is ripe.

[单选题]B．efore starting the engine, the air bottle should be ____.A．pumped upB．loadedC．dischargedD．closed

[单选题]Before hydraulic starting of an engine on a covered lifeboat，what need NOT be checked?（）A . Fuel supply line valveB . Pressure registered on the accumulator gaugeC . Cold-spark voltage readings test lampD . Engine stop control

[单选题]Before a marine diesel engine is started the cylinders and pistons must be （）.A . cooled to appropriate temperatureB . warmed up gradually to appropriate temperatureC . opened up and renewedD . ground and polished

[单选题]The diesel engine must be started before it can run by it self For this purpose （） has to be used.A . a starting systemB . the starting airC . a starting operationD . A, B and C

[单选题]Before starting the engine the air bottle should be （）.A . pumped upB . loadedC . dischargedD . opened