雅思詞匯之可生物降解的

　　biodegradable[可生物降解的]

　　-eg: biodegradable garbage[可生物降解垃圾];

　　motor vehicle exhaust[汽車尾氣]

　　-eg: motel vehicle exhaust leads partly to the greenhouse effect.;

　　be in short supply[供應不足]/shortage/scarcity/lack of

　　-eg: petrol is in short supply.