[Literal Meaning]
like/the sun/high noon
like the sun at high noon
[解释]
好像太阳正处于天顶。比喻事物正发展到十分兴盛的阶段。
[Explanation]
at the apex of one's power
[例子]
就在他的事业如日中天的时候，一场重病让他不得不彻底休息。
[Example]
When his career was flourishing like the green bay-tree, a serious illness made him rest eventually.
[英文等价词]
in one's or its prime
eat high on the hog
参考例句：
Like the sun in midsky-to be very influential如日中天
In the full flush of success, nothing was an obstacle.在成就如日中天时,其势锐不可当。