鉴于大家对英语英语考证PETS写作十分关注，我们编辑小组在此为大家搜集整理了“2013年关于PETS4写作精选短语”一文，供大家参考！
2013年关于PETS4写作精选短语
Seasonal variation
predictable changes in sales volume, business activity, or inventory due to the changes of seasons during the year
EXAMPLE:
Seasonal variation within the American toy industry is heavily influenced by Christmas holiday shopping.