pass off
1. To offer, sell, or put into circulation (an imitation) as genuine: pass off glass as a gemstone.
2. To present (one's self) as other than what one is: tried to pass himself off as a banker.
参考pass off 的第一种解释,enging break in and pass off应该解释为:发动机磨合及运行
Engine break-in, also known as running in, is the procedure of conditioning the new engine of a vehicle by following specific driving guidelines during the first few hours of its use.