the tomb his bird was eaten by a snake.A. As soon as enteredB. When entering intoC. On e

问题补充：

the tomb, his bird was eaten by a snake.

A. As soon as entered

B. When entering into

C. On entering

D. Upon entered

答案：

A. As soon as entered

B. When entering into

(答案→)C. On entering

D. Upon entered

解析：考查”一…就…”的表达：A项是as soon as he entered，B是enter后面不加介词，C项是on doing sth，D项upon entering，句意是：一进入这个坟墓，这个鸟就被蛇吃了。选C。