您要查找的是不是：
- Many natural materials are becoming scarce. 许多天然原料越来越少。
- He's in a bad mood, so I'll make myself scarce. 他情绪不好，我得躲著点。
- Good fruit is scarce in winter and costs a lot. 好的水果冬天难得见到，而且价格昂贵。
- I do not know why acids eat in metals. 我不知道酸腐蚀金属的原因。
- Food was scarce throughout the war. 在战争期间食物匮乏。
- The need to economize scarce energy resources. 节约使用稀有能源的必要性
- Food and fuel were scarce in this region. 这地区食物和燃料都很缺乏。
- Copper and gold are both metals. 铜和金都是金属。
- Metals undergo expansion when heated. 金属加热时会膨胀。
- It follows that acids eat in metals. 由此可知，各种酸对金属都有腐蚀作用。
- Memory has been shown to reside in some metals. 已经证实，记忆存在于某些金属中。
- Metals expand when they are heated. 金属遇热则膨胀。
- She knows why the metal is the good conductor. 她知道金属为什么是好的导体。
- Now that oil is scarce, the fate of the motor car is uncertain. 既然石油短缺，那么汽车将来会怎样就难以预料了。
- Some metals weld better than others. 有些金属容易焊，有的不容易焊。
- Metals contract in cold weather. 金属在寒冷的天气里收缩。
- Certain metals are attracted to a magnet. 某些金属会受磁石的吸引。
- They made themselves scarce when they saw the teacher coming. 他们看到老师来了就溜走了。
- Metals contract as they get cooler. 金属遇冷则收缩。
- Hotel accommodation was scarce during the Olympic Games. 奥运会期间，旅馆房间很难找。
