A.20℃±1℃ B.25℃±1℃ C.30℃±1℃ D.37℃±1℃
A.丁烷 B.乙炔 C.氫氣 D.天然氣
A.10s B.20s C.30s D.40s
A.五號 B.五號黑體 C.四號 D.四號黑體
A.8 B.10 C.15 D.20