6.03×8的积中有一位小数。
如图,在△ABC中,D、E分别是AB、AC的中点,若BC=10,则DE=____.
用如图甲所示的实验电路探究“电流与电阻的关系”,请解答下列问题:
We should try to solve the food safety. It is a serious _______ in our country.
—About twice a week.