When current is withdrawn from the battery, chemicalactions take place to produce the flow of current.
当从蓄电池中提取电流时，蓄电池内发生化学作用，使电流流动。
2
When sulfuric acid is placed between the plates, chemicalactions take place that remove electrons one group of plates and mass them at the other.
当硫酸放入极板组之间，就会发生化学反应，把一块极板中所含的电子聚结到另一极板。
3
The external causes include the effects of environmental and service conditions to which concrete is subjected, such as weathering, chemicalactions and wear.