混合动力汽车已经面世,混合动力汽车(Hybrid Electrical Vehicle,简称HEV)是指同时装备两种动力——热动力源(由传统的汽油机或者柴油机产生)与电动力源(电池与电动机)的汽车。混合动力汽车主要由一台内燃机和一台电机组成,这台电机既可以充当电动机也可以充当发电机。汽车启动时内燃机不工作,主要由蓄电池提供动力,当汽车需要高速行驶或电池电量过低时,改由内燃机工作,一方面能为汽车提供动力,同时能通过电机给蓄电池充电。
古希腊人崇尚人体美,无论是雕刻作品还是建筑,他们都认为人体的比例是最完美的,干什么都必须按照人体各部分的式样制定严格比例。这充分体现了古希腊人强调( )
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Hello, I'm Anna. This is my room. It is not very big ____it's comfortable(舒适的)and it's very ____.This is my bed. My desk and my chair are next to (在 ……旁边)the bed. ____are my pens? They're in my pencil box. What's that ____the desk? It's a model plane. My parents are Alan and Mary, and ____room is next to mine.
“神舟飞船”与“天宫一号”成功对接后携手遨游太空.“神舟飞船”以“天宫一号”为参照物是 ____的,以地球为参照物是 ____的.