About half an hour before the engine is required， cooling water at （） must be circulated.
举一反三
- The __________ must be circulated between moving engine parts to prevet metal-to-metal contact. A: coolant B: fuel C: engine oil D: water
- The pH value of water in a diesel engine closed cooling water system should be maintained between （）.
- A three-way thermostatic control valve regulates the diesel engine cooling water temperature by passing a portion of the water _____.
- When preparing an engine for running, the cooling water temperature should be _______. A: kept at a proper level by a coole B: aised to about 80℃ by a heate C: aised gradually D: lowered to about 60℃
- It is about ______ walk from here to the office. A: half an hour's B: half a hour's C: half an hours'