A.美觀 B.防止漏氣 C.防止爆炸 D.保護(hù)瓶閥
A.305℃ B.350℃ C.450℃ D.560℃
A.2.17~9.5% B.1.15~8.4% C.1.7~9.6% D.3.2~6.4%