n.極性；磁性引力；兩極
Polarity is inherent in a magnet. 極性是磁鐵的固有性質。
Note the polarity of the voltage drop across R. 注意R上電壓降的極性。
The hydrophobicity is related to molecular volume and polarity. 分子的疏水性跟分子的體積和極性有關。
The field is strongest at the poles, diminishes at the equator, and differs in polarity from the Northern to the Southern Hemisphere. 南北兩極的磁場最強，赤道上磁場較為微弱，而各地的磁性也會因緯度而改變。
n.雙極性
