fell的過去式是什么

　　He lost his balance and fell to the ground.

　　他失去平衡摔倒在地上。

　　He fell, striking his head on the edge of the table.

　　他摔倒了，頭碰在桌棱上。

　　The results of the survey fell into two distinct groups.

　　調查結果分為截然不同的兩組。