sky是可數名詞嗎

　　sky雙語例句：

　　A red sky at night often indicates fine weather the next day.

　　夜空呈紅色往往預兆第二天天氣晴朗。

　　The stars were points of light in the sky.

　　天空中的點點光亮就是星星。

　　Several people described seeing strange lights in the sky.

　　好幾個人都說看到天上出現了奇異光芒。

　　The sky suddenly went dark and it started to rain.

　　天空驟然轉暗，隨即下起雨來。

　　The sun was low in the sky.

　　太陽低掛在天空。