We all know that it is 1to keep healthy. But not all people know2to keep healthy.
After five days' hard work, we need to have a good rest at weekends. But it seems that some don't know how to spend weekends in the right way. They enjoy3 cards at night and don’t go to bed until midnight. Some gamble (赌博) all night. They forget that to get4sleep is good for health. Some never get up early in the5 and take some exercise. It is true that doing exercise is very important for us to keep 6. Some smoke（抽烟）7. Some drink too much wine（酒）. 8 too much is harmful (有害) to the body. Some eat too much rich food and get fatter and fatter. If you are much too fat, you may always 9tired. Vegetables are good to the body. But some don’t like eating vegetables. 10is also very good to body. As a saying (谚语) goes, "An apple every day keeps the doctor away." So don’t forget to eat some fruit.

由表中数据得到线性回归方程 $\widehat{y}$ =﹣2x+a，当气温为﹣4℃时，预测用电量均为（   ）

比尔·布莱森在他的《万物简史》里介绍了超级火山的巨大破坏性。以美国为例，__①__境内有一座超级火山喷发，__②__其产生的巨大能量将摧毁数千公里范围内的所有东西，无数人会因此丧命，__③__会导致整个国家被深达6～20米的火山灰覆盖，随后__④__会出现其他许多可怕后果。  __⑤__目前人类还无法预测美国超级火山会在何时喷发，__⑥__了解了它的杀伤力有利于我们制订各种减损预案。