发生于

Senile dementia is a series of chronic progressive mental deterioration occurring in or pre the geratic period.

老年期痴呆是发生于老年期和老年前期的一组慢进行精神衰退。

These events occurred in 1909.

这些事件发生于1909年。

These tumors, to date, have occurred over a wide age range in postpubertal females, are characteristically unilateral, and confined to the ovary at presentation.

到目前为止，这些肿瘤发生于青期后期女的一大段年龄范围内，特征地出现于，发生于卵巢。

Therefore, the albitization of plagioclase is shown in the early stage of diagenesis and albitization of potash feldspar appears only in the late stage of diagenesis.

因此，斜长石的钠长石化可见于成岩早期，而钾长石的钠长石化只发生于成岩晚期。