Two million years ago, a cave-studded aquifer lay beneath an undulating plain of shallow, wooded valleys and rolling hills.
200万年前，在树木丛生的谷地和波状丘陵地带的起伏平原之下，是洞穴密布的地下蓄水层。
2
It may make quantitive account of skew ratio from plain roller rolling square bar.
此模型可对平辊轧制矩形件产生的脱方量进行定量计算。
3
The results show that nitrogen has remarkable influences on rolling contact fatigue life and plain strain fracture toughness, and little influences on wear resistance.