The most ancient parts of the continental crust are 4000 million years old.

　　該大陸地殼最古老的那些部分有40億年了。

　　Lowered sea levels exposed the shallow continental shelf beneath the Bering Sea.

　　下降了的海平面使白令海底的淺大陸架露了出來(lái)。

　　The quota system was modelled on those operated in America and continental Europe.

　　配額制是仿照美國和歐洲大陸所施行的那些制度制定出來(lái)的。