For example, did you know that 1 in 4 teenagers has tried marijuana?
比如,你是否知道4个青少年中就有1位曾经吸过大麻?
The remains of plants and animals that lived on land are much more rarely preserved, for there is seldom anything to cover them over.
曾在陆地上生活过的动植物的遗体被保存下来的更为罕见,因为陆地上几乎没有什么东西覆盖它们。