Sī / jī / tōng / guò / zhuàn / sù / biǎo / pàn / duàn / fā / dòng / jī / shì / fǒu / yùn / zhuǎn / zhèng / cháng司机通过转速表判断发动机是否运转正常。The driver uses the tachometer to determine whether the engine is running properly.