it is snowing是什么意思,是不是现在进行时态

it is snowing是什么意思,是不是现在进行时态 请问It is snowing.的述谓结构是什么?是BE(SNOWING)吗?还是（SNOW）? It is snowing now.It______yesterday. Is it snowing right now? It is snowing heavily (介词) it is snowing now.it什么yesterday it is very cold today,because it is( )这个空填什么 是 snowy还是 snowing 下雪（词组）怎么说?是It is snowing now.还是It is snowying now. It is snowing very hard .同义句 It is snowy 还是snowing today IS it snowing today怎么回答 it is snowing weather 还是snowy weather It is snowing heavily now.改为感叹句 when it is snowing什么意思 是“How heavily it is snowing!”还是How heavy it is snowing!是英语的“How”感叹句,顺便告诉我下What的感叹句怎么写, it is snowing right now?right it is snowing right now? it is very cold.it is snowing h_____ How heavily it is snowing now!中,为什么不能用“heavy”代替“heavily”?为什么?是因为snowing是动名词的关系吗？