问个雅思小作文的问题.
However there was a little fluctuation in Beef between 1979 and 1984 when consumption declined to 170 grams in 1981 before a quick ascendant up to a peak(250 grams) in 1984.这是我写的句子,那里那个when引导的从句可以这样用吗?when引导从句时后面的从句是指那一段时间发生的事情还是那个时间点发生的事情?