新概念英语第三册逐句精讲语言点 第42课 现代洞穴人 (3)

　　Precautions of this sort are necessary, for it is impossible to foretell theexact nature of the difficulties which will confront the potholer. The deepest knowncave in the world is the Gouffre Berger near Grenoble. It extends to a depth of 3723feet. This immense chasm has been formed by an underground stream which hastunnelled a course through a flaw in the rocks. The entrance to the cave is on a plateauin the Dauphine Alps. As it is only six feet across, it is barely noticeable.

　　9.Precautions of this sort are necessary, for it is impossible to foretell the exact natureof the difficulties which will confront the potholer.

　　作出这样的准备是必要的，因为无法预见到洞穴探险者究竟会遇到什么性质的困难。

　　语言点:sth.be necessary的意思是“做某事是有必要的”。

　　10.The deepest known cave in the world is the Gouffre Berger near Grenoble.

　　世界上最深的洞穴是格里诺布尔附近的高弗伯杰洞。

　　11.It extends to a depth of 3723 feet.

　　深达3,723英尺。

　　12.This immense chasm has been formed by an underground stream which hastunnelled a course through a flaw in the rocks.

　　这个深邃的洞穴是由一条地下暗泉冲刷岩石中的缝隙并使之慢慢变大而形成的。

　　13.The entrance to the cave is on a plateau in the Dauphine Alps.

　　此洞的洞口在丹芬阿尔卑斯山的高原上。

　　14.As it is only six feet across, it is barely noticeable.

　　仅6英尺宽，很难被发现。

　　语言点:句子结构分析:as引导原因状语从句，交代“很难被发现”的原因。