He leans over backwards to please his immediatesuperior.
lean over backwards字面理解就是：“身体使劲地向后倾斜”，这种姿势对于一般人来说应该很难做到，而且做起来也很难受。由此引申而来的意思就是，为了做某事而把自己置于不舒服的位置，也就是我们说的“竭尽全力、拼命地”的意思。因此，当美国人说"He leans over backwards toplease his immediate superior."时，他/她要表达的意思就是:"He tries to please his boss tooth andnail."、"He tries his best to please his boss."。
Terry: I saw Jack driving the boss home yesterday.
Benjamin: He leans over backwards to please his immediate superior. Otherwise the bosswouldn't value him so much.
①Yeah, that's why many colleagues are discontent with him.
②He is a small tag-along kid who follow whoever seems to have the power.
③Otherwise, he has to live on air.
④He does not really get right on the job.
1. superior n. 上级，长官
Other army units are completely surrounded and cut-off from communication with theirsuperiors.
The company president, and my immediate superior, was the dynamic Harry Stokes.
His effort is ignored by his superior.
2. tooth and nail 拼命地，全力以赴地
We fought tooth and nail to get our plans geniuspted.
That woman fought tooth and nail during the war to protect her children.
That company has been fighting tooth and nail to stay in business since it got morecompetition.
3. discontent adj. 不满的
She seems discontent with her salary.
So he must be discontent because this would be the only way to keep you within your limits.
所以他必须去不满 因为这是唯一方法 来保持你的底限
The strikes were a sign of discontent with poor pay.