1.dune n.沙丘
例句：The dunes usually migrate inland.
沙丘常往内陆移动。
2.observe v.观察,遵守,注意到,纪念
例句：It is difficult to observe any change in his expression.
很难看出他的表情有什么变化。
3.quartz n.石英
4.dissolve v.使溶解,使融化
例句：Erosion has dissolved acres of topsoil.
侵蚀作用已使大量表土层流失。
5.scratch v.搔,抓,挖出,擦
例句：The laboratory scratched that experiment for this year.
实验室今年取消了那项实验。
Hard chalk scratches the blackboard.
硬粉笔会把黑板划坏。
6.transverse a.横的,横向的
例句：Judging from the transverse section of the bread, it was with filling.
从面包的横切面可以看出它是夹心的。
7.intense a.非常的,强烈的,紧张的,热情的
例句：We needed to rest from the intense heat of the desert.
我们得休息一下，避开沙漠的酷热。
1.The minerals calcium and sulfur were at the bottom of the ocean.
at the bottom of在...之底部
例句：There's a pub at the bottom of the road.
路的尽头有一家酒馆。
Carelessness is at the bottom of all great mistakes.
粗心大意是一切重大错误的根源。
2.About twenty-four-thousand years ago, it rained a great deal in the area.
a great deal很多,大量,…得多
例句：His words caused a great deal of dissension.
他的话引起了许多争论。
I can't say the news concerns me a great deal.
我说不上这消息与我有多大关系。