微波炉的外壳用不锈钢等金属材料制成，装食物的容器则用绝缘材料制成．微波炉内的磁控管能产生振动频率为2.45×10⁹HZ的微波，直达食物内部5cm深，使食物中的水分子也随之振动，剧烈振动产生大量的热能被食物吸收，于是食物“煮”熟了．用微波炉烹饪的速度比其它炉灶快4至10倍，热效率高达80%以上．微波炉由于烹饪的时间很短，能很好地保持食物中的维生素和天然风味．比如，用微波炉煮青豌豆，几乎可以使维生素C不损失．

另外，微波还可以消毒杀菌，解冻，干燥，当然过量的微波辐射对人体有害．

①突破传统的束缚是经济体制调整和创新的前提

②因为积重难返，苏联改革步履艰难，效果不大

③社会主义改革具有复杂性、艰巨性和曲折性

④改革必须具有实事求是的科学精神

   Can you imagine astronauts' everyday life in space? They also need to eat,  sleep, exercise and relax. They do the same things as us, but they do them differently.
   On Earth, we put food on a plate. Gravity holds the food down and keeps it on a place. But there is almost no gravity in space, so food can float （漂浮）away, and astronauts must eat carefully.
   Sleeping is very different in space. Some astronauts like to float in the air, but most like to be in a sleeping bag. They tie the bag to a wall so that they won't float away at night.
   Exercise is very important in space. On Earth,  your legs carry your body,  but in space, astronauts float, so they do not use their legs often. This is very bad for their legs, so they must exercise for thirty minutes every day.
   After a day's work, astronauts relax. They may listen to music, read, watch films, play games, or talk to their friends and families on the radio. Sometimes they just enjoy floating in the air.