他在车库里改装了一辆热力车，发动机声音听起来很震撼。

He modified a ___hot-rod in his garage, and the engine sounds incredibly powerful.

他花了整个夏天改装他的老爷车，想把它变成一辆超级快车。

He spent the whole summer ___hot-rodding his old car to turn it into a super fast vehicle.