【用戶】已考上107正式英文老師:

【年級】大二下

【評論內容】（C）一年內不利的氣候條件。當氣候不佳，水分不足時，年輪會生長得比較窄。Growth rings, however, are not always the same thickness. They vary for several reasons. Environmental factors rigidly control the degree of growth of an annual ring or determine whether, in fact, an annual ring appears or not in any particular year. Thus in a specific locale or, more accurately, a specific climatic province, tree-ring counts will reflect climatic conditions and variations due to inequalities of climate from year to year. In years with abnormal drought, for example, narrow rings are produced and sometim...