Gōng / chéng / shī / zhèng / zài / jiǎn / chá / fā / dòng / jī / lǐ / de / tū / lún / shì / fǒu / mó / sǔn工程师正在检查发动机里的凸轮是否磨损。The engineer is checking whether the cam in the engine is worn.