Beijing, the  capital  of China ,is one of ____cities in the world.[ ]

A. the biggest

B. bigger

C. much bigger

D. big

如烘箱内起灭，正确做法是（）

A.先关闭电源

B.不打开烘箱门等其自灭降温

C.迅速打开烘箱门灭火

D.用水浇烘箱