81÷9=____
63÷9=____
6×9-6=____
9×3-7=____
4×9+5=____
9×7-3=____
A. I can't find my book.
B. Read the newspapers to old people.
C. Over there.
D. Because we can reuse them.
E. Yes.
我国铁农具开始出现于( )
图所示的电路,闭合开关后,当滑片P向左移动时,下列说法正确的是()