1 in the tree 一般指外来的东西在树上,不是树本身所有,如猫、猴、鸟等在树上。
He saw a cat in the tree. 他看见树上有一只猫。
Jack is in the tree . He can't get down. 杰克在树上,他下不来了。
2 on the tree 通常指树本身长出的东西,如枝、叶、花、果等。
There are many apples on the tree . 树上有许多苹果。
She's picking oranges on that tree . 她在摘那棵树上的橘子。