There're two reasons for this: first, they live in the active layer, which, remember, contains water that doesn't penetrate the permafrost.

造成这种情况的原因有两个：首先，它们生活在活动层中，请记住，活动层中包含的水不会渗透永久冻土。

youdao

First produced in a lab back in 2004, graphene is essentially a single layer of pure carbon atoms bonded together in a honeycomb lattice so thin it's actually considered two-dimensional.

石墨烯最早在2004年诞生于一个实验室，本质上是一层由纯碳原子组成的蜂窝状晶格层，薄到竟被认为是二维物质。

youdao

Note the two-layer partitioning system in OpenBSD: the first step sets up traditional fdisk-viewable partitions, while the second disklabel step sets OpenBSD sub-partitions.

注意OpenBSD中的两层分区系统：第一步是建立传统的fdisk可视分区，而第二个disklabel步骤将设置OpenBS d子分区。

youdao