concentration variation的用法和樣例：
例句
- Although all plants normally contain fluorine, the concentration varies greatly.
雖然在正常情況下，所有的植物都含氟，其濃度變化很大。 - Three parameters are designed to study the function of photocatalyst, which are spray layers of photocatalyst, spray area ratios and concentration of formaldehyde.
每小時紀錄甲醛濃度變化，以該濃度變化評估二氧化鈦光觸媒去除甲醛之效能。
