A:because of; because
B:because; because of
C:because; because
D:because of; because of
白磷着火点为40℃,红磷着火点为240℃,它们在空气中燃烧都生成有毒的白烟﹣﹣五氧化二磷,五氧化二磷易溶于水.
— Let's go dancing tonight!
— Sorry, I ______.I have to go to a meeting.