在某森林的固定位置和固定时间，用固定数量鸟网捕捉的方法，统计大山雀种群数量。连续10年内得到如下图所示的曲线(图中λ表示该种群数量是前一年种群数量的倍数)，有关叙述错误的是

在冷空气和暖空气交会面上常常形成降水，如图表示的降水类型是（　　）

纷繁复杂的经济生活中存在许多“双刃剑”现象，即同一事实或措施，有可能产生截然不同的两种效果。下列描述中，正确体现这一现象的是（    ）

①财政收入过多会影响企业生产和居民生活，财政收入过少会导致国家宏观调控能力下降

②人民币贬值不利于扩大海外投资，但有利于我国企业扩大出口

③免征小排量汽车的购置税会增加市场需求，同时汽车供应量也会增加

④今年3月猪肉价格上涨28.4%，一定意义上有利于养殖户，但不利于消费者

    “Early to bed, early to rise, makes a man healthy, wealthy(财富) and wise (智慧).”

    This is an old English saying (谚语)．Did you hear of it? It means that we must go to bed early and ____ up early in the morning．Then we will keep ____．We'll also be rich and clever.

    This is true．The body must have ____ sleep to be healthy．Children of young age should have ten ____ sleep every day．Children who don't have enough sleep can't do their work very well．They won't be clever and they may not become rich!

    The body also needs ____．Walking, running, jumping, swimming and playing games are all exercise．Exercise the body strong(强壮).

    Exercise also helps the blood(血) to ____ around inside the body．This is very important．Our blood ____ food to all parts(部分) of our body．The head also needs blood． Exercise helps us to think____.