一般可燃物燃烧时,当空气中的含氧量降低到()时,火就会熄灭.
A.16%
B.12%
C.11%
参考答案:C
—Would you tell me__________you want your tea , with sugar or milk ?
—Sugar , please .
A.whether
B.when
C.what
D.how
在面向对象方法中,类之间共享属性和方法的机制称为______。