Tra từ fluctuate - Từ điển Oxford Advanced Learner 8th

fluc·tu·ate AW [fluctuate fluctuates fluctuated fluctuating] BrE [ˈflʌktʃueɪt] NAmE [ˈflʌktʃueɪt] verb intransitive
to change frequently in size, amount, quality, etc, especially from one extreme to another
Syn: ↑vary
•fluctuating prices
•The documentary follows the fluctuating fortunes of one marketing company.
•~ between A and B During the crisis, oil prices fluctuated between $20 and $40 a barrel.
•+ adv./prep. Temperatures can fluctuate by as much as 10 degrees.
•My weight fluctuated wildly depending on how much I ate.
•My mood seems to fluctuate from day to day.
•The rate of inflation has been fluctuating around 4% for some time.
Derived Word: ↑fluctuation
Verb forms:

Word Origin:
mid 17th cent. (earlier (late Middle English) as fluctuation): from Latin fluctuat- ‘undulated’, from the verb fluctuare, from fluctus ‘flow, current, wave’, from fluere ‘to flow’.

Example Bank:
•The number of boys at the school fluctuates around 100.
•The number of students fluctuates around 100.
•The number of unemployed fluctuates between two and three million.
•Traffic congestion fluctuates according to the time of day.
•constantly fluctuating patterns
•During the crisis, oil prices fluctuated between $30 and $50 a barrel.