The glass blocks covering the walls and roof allow natural light to illuminate the entries and extend below-grade through the diagonal space of the stairs and escalators.

玻璃块覆盖的墙壁和屋顶可以让光线照射进来并且向下延伸，通过楼梯和自动扶梯实现对角空间效果。

youdao

youdao

I am one grade below him.

我比他低一年级。

《新英汉大辞典》

All improvements, whether on Vanderbilt or on the below-grade subway platforms, is quite innovative.

WSJ: Not Visionary Enough | By Julie V. Iovine

Corporate bonds rated BBB are yielding 8%, while their below-investment-grade BB brethren yield 9%.

FORBES: Magazine Article

The risk premium in financial markets comes in as Treasury yields move up and fewer below-investment-grade debentures stop trading like yesterday's sardines.

FORBES: Uncle Sam: Not Too Big To Fail