zhè / zuò / shí / kū / de / dǐng / bù / chéng / qióng / lóng / xíng / xiǎn / de / shí / fēn / kāi / kuò

这座石窟的顶部呈穹窿形，显得十分开阔。

The ceiling of this grotto is dome-shaped, making it look very spacious.