新概念英语四册课堂笔记The范文仅供参考，自行编辑使用新概念英语四册课堂笔记The Earth BeneathL52 The Earth BeneathAn earthquake comes like a thief in the night, without warning.It was necessary, therefore, to inventinstruments that neither slumbered nor slept.Some devices were quite simple.one, for instance,consisted of rods of various lengths and thicknesses which would stand up on end like a shock came it shook the rigid table upon which these stood.If it were gentle, only the moreunstable rods fell.
