启动外围设备的工作由（）来完成。 用户程序。 操作系统。 用户。 外围设备自行启动。
When two oil separators are working in series, they should work with （） both as clarifiers。 first one as clarifiers, second one as purifier。 both as purifiers。 first one as purifier, second one as clarifier。
（）期是指稻穗从顶端茎鞘里抽出到开花齐穗这段时间，一般5-7天。
How should you warm up a diesel engine that has not been run for some time? （） Run it at minimum speed for a period of time。 Run it at half speed for a period of time。 Bring it to top speed immediately。 Inject ether into the air intake。
Concerning the management of sewage treatment plant using activated sludge, which of the following is correct?（） the plant should be prohibited to supplying air。 the plant should work at intervals。 the plant should be added disinfector in time。 we should check strength of activated sludge, ivory-white color is best。
裸机上的第一层扩充是（）。
