心电图上标明心跳次数.A electrocardiogram records the heartbeat.心电图和脑电图在现代医学中是非常珍贵的诊断工具.Both electrocardiograms and electroencephalograms are invaluable diagnostic tools in modern medicine.心电图可能是最广为应用的监测仪.Perhaps the single most wi...
薪材日益昂贵和稀缺,既买不起又拣不到.Fuelwood is becoming too expensive to buy and too scarce to gather.薪材短缺是毁林后果的最明显和最引人注目的实例.Firewood scarity offers the most visible and dramatic example of deforestation's effects....