A. Urge their governments to control litter and waste. B. Make anti-polllution advertisements. Cut down the use of oil and other oil products. D. Reduce unnecessary buying and careless disposal of waste.
A. 热电极材料和两端温度 B. 热电极材料 C. 热电极粗细和两端温度
A. 半导体热敏电阻的α大、且为负值 B. 半导体热敏电阻的α大、且为正值 C. 半导体热敏电阻的α小、且为负值
A. 电阻温度系数大 B. 电导率低 C. 热电势大 D. 热惯性大
A. 正常 B. 不正常