A.6~7歲 B.6~9歲 C.7~8歲 D.7~9歲 E.8~9歲
A.10s B.30s C.60s D.2min E.5min
A.穿破牙齦時(shí) B.合面露出時(shí) C.對(duì)頜牙也已萌出時(shí) D.牙萌出后達(dá)到合平面是 E.無(wú)時(shí)間限制