In the second stage, the primary follicles develop into secondary and eventually tertiary, or graafian follicles.

第二阶段，初级卵泡形成次级卵泡，最终形成第三极卵泡，即格拉夫卵泡。

The second stage takes roughly 70 to 85 days and results in a few fast-growing graafian follicles.

第二阶段大概要经历70到85天，期间少数格拉夫卵泡快速生长。

During the follicular phase of each menstrual cycle, the few fast-growing graafian follicles enter the third stage of development.

每次月经周期的卵泡期，少数生长迅速的格拉夫卵泡，会进入成熟的第三个阶段。

The third stage of follicular development starts when the graafian follicles are ready and occurs during the follicular phase of the menstrual cycle.

第三阶段——格拉夫卵泡准备好了，在月经周期中排卵。

In a graafian follicle, a central cavity called the antrum forms within the follicle, and the granulosa cells secrete a nourishing fluid for the primary oocyte directly into that antrum.

格拉夫卵泡的中间会形成一个空腔叫做卵泡腔，而颗粒细胞会为初级卵母细胞分泌营养液，直接排入卵泡腔。