darkening rate的用法和樣例：
例句
- The increased darkening of the sky toward the right indicates the darkened atmosphere created by the passing shadow cone of the total solar eclipse.
右側的天空逐漸變暗這就表明日全食的影錐通過了地球的大氣層，使得那裡變暗。 - It may serve, let us hope, to symbolize some sweet moral blossom, that may be found along the track, or relieve the darkening close of a tale of human frailty and sorrow.
它可作為，讓我們希望，象徵甜蜜的一些道德開花，這可能是沿著軌道發現，或減輕人類的脆弱和悲傷的故事變暗關閉。
