单项选择题
The inner part of the condenser should be cleaned with （）.
A.gas oil B.diesel oil C.chemical compound D.Freon-12
单项选择题 The injector pump is operated by a cam which drives the plunger （）.
单项选择题 The injector pump is operated by a cam which drives the （） up and down.
单项选择题 The injector pump is operated by a cam which drives （） up and down.
