透明物体的颜色是由它_________的色光决定的，而不透明物体的颜色是由它__________的色光决定的。
通过；反射
电路的三种状态是指__________、__________和__________。
It is said that sandstorms will become more __________ as a result of global warming.[ ]
A. frequent
B. normal
C. formal
D. rare
