例句與造句

1. The "'HK P9 "'is a semi-automatic pistol from Heckler & Koch in 9?9mm Parabellum and the first to use a variation of roller delayed blowback system in a pistol format and polygonal rifling now common in H & K designs.
2. It's difficult to find roller delayed blowback in a sentence. 用roller delayed blowback造句挺難的