练习材料:
Lesson30-2 Exploring the sea-floor
A burst of activity associated with the laying of submarine cables soon confirmed the challenger's observation that many parts of the ocean were two to three miles deep, and the existence of underwater features of considerable magnitude.
Today, enough soundings are available to enable a relief map of the Atlantic to be drawn and we know something of the great variety of the sea bed's topography. Since the sea covers the greater part of the earth's surface, it is quite reasonable to regard the sea floor as the basic form of the crust of the earth, with, superimposed upon, it the continents, together with the islands and other features of the oceans. The continents form rugged tablelands which stand nearly three miles above the floor of the open ocean.
应用配置:L0+L4
知识笔记:magnitude/mægnəˌtud topography/təˈpɑgrəfi crust/krʌst continents/kɑntənənt srugged/rʌgəd
练习感悟:用时37分钟。最后这一版中间有点卡壳,没有再调整。
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