Measuring the electrical conductivity of many chemical solutions is difficult if the ionic concentration is very low. 如果离子浓度非常低，测量许多化学溶液的电导率是很困难的。
Combining two chemical solutions whose components each appeal to a different taste is a complex psychophysiological event. 结合两种具有不同味道的化学溶液是一个复杂的生理心理活动。
