- How often does she have dancing classes?
- _________.
A:On Saturday afternoon
B:At 9 o'clock
C:Once a week
根据2871÷33=87,可以推算出:3.3×0.87=____,28.71÷0.87=____。
某种商品每件的进价为30元,在某段时间内若以每件x元出售,可卖出(100﹣x)件,则将每件的销售价定为____ 元时,可获得最大利润.
看书一个小时后,向远处眺望一会儿,可以预防近视眼,主要原因是( )