— Mike worked hard but he failed the exam again.
— _______________.
A：Good luck
B：I don't think so
C：Sound like fun
D：I am sorry to hear that
下列现象中，属于规律范畴的是（ ）
下列关于声音的说法中不正确的是（ ）
15×(6＋12)=15×____＋15×____
