题目内容（请给出正确答案）

[主观题]

For a fire to begin there must be present a combustible material, oxygen or air to ______

combustion, and a source of heat at a temperature high enough to start combustion.

A.begin

B.support

C.last

D.extinguish

提问人：网友wuxuesong 发布时间：2022-01-07

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