A:石油的蕴藏量是无限的
B:石油是“清洁燃料”
C:石油主要由多种有机物组成
D:石油除了作燃料,不能再开发利用了
汗液的成分中不含有的成分是( )
—I don't think so. The key to his good grades is his hard work, not good luck.