C602 Making a Fool of Yourself

An engine, after 150 hours of experiments, what should it be like?

In a test car, there would be all kinds of malfunctions. For example, if an oil pipe was broken, the lubricant would be everywhere. But now, this engine was clean.

Did you clean it?

Hearing this, the person-in-charge suddenly thought of something and his face revealed a trace of panic. After a while, he calmed down and said