伊卡莱姆的ScalersTalk第四轮新概念朗读持续力训练Day

练习材料：

Lesson42-5 Recording an earthquake

it would be up and down, to and fro and from side to side. Instruments have been devised and can be so placed that all three elements can be recorded in different graphs.

When the instrument is situated at more than 700 miles from the earthquake centre, the graphic record shows three waves arriving one after the other at short intervals. The first records the arrival of longitudinal vibrations. The second marks the arrival of transverse vibrations which travel more slowly and arrive several minutes after the first. These two have travelled through the earth. It was from the study of these that so much was learnt about the interior of the earth. The third, or main wave, is the slowest and has travelled round the earth through the surface rocks.

应用配置：L0+L4

知识笔记：graphic/    longitudinal/    transverse/    interior/

练习感悟：用时33分。晨读。这篇课文算是超长，分了5个段落。