D. on
on 在句子中是介词,译为 在...表面上
句子应为：
The bird snatched the snake from the ground. So the snake had been on the ground.
整句翻译：
鸟把蛇从地上抓走了,所以蛇原来是在地面上.你的意思是这个句子是少了一个"had"?这个句子是否应该是"The bird snatched the snake from the ground. So the snake had been on the ground."?谢谢!对，前句的动词 ‘snatched’ 是过去式，后句的 ‘had been'是过去完成式。