下列各物质中，氮元素化合价最低的是（ ）
将下列图片与相应的句子连线。
① ____ A. I like winter. I can skate.
② ____ B. I like spring. I can ride a bike.
③ ____ C. I like summer. I can swim.
④ ____ D. I like autumn. I can fly a kite.
____ A. I like winter. I can skate.
____ B. I like spring. I can ride a bike.
____ C. I like summer. I can swim.
____ D. I like autumn. I can fly a kite.
