the sky is______dark为何可以同时用gets和is getting

the sky is______dark为何可以同时用gets和is getting the sky is getting darker and danker The sky gets dark The weather gets cold The weather is getting cold 两句一样吗 第二句怎 The earth is getting warmer and warmer.As the earth gets war Autumn comes ,it gets cooler and cooler .The sky is blue and the teacher( )his students.a gets on well with b is getting why is the old man getting nagging when he gets older? 系动词和助动词区别It's getting cool is是助动词 getting 是主要动词吗It gets cool We decided to find a place to stay in,as the sky is getting It gets colder and colder 和 It is getting colder and colder有 The sky is The sky is mine