蚍蜉撼树的英文：
[Literal Meaning]
ant/shake/tree
like an ant trying to shake a big tree

[解释]
蚍蜉：蚂蚁。蚂蚁想摇动大树。形容自不量力。

[Explanation]
to overestimate one's power

[例子]
你想把他从市长的位置上弄下来，简直就是蚍蜉撼树。

[Example]
If you want to remove him from the mayor's office, it is like an ant trying to shake a big tree.

[英文等价词]
to put a quart into a pint pot

Ants on the locust tree assume a great-nation swagger; and mayflies lightly plot to topple the giant tree.
蚂蚁缘槐夸大国,蚍蜉撼树谈何易