"It's a horizontal motion of two pieces of the Earth's crust on either side of a vertical crack in the Earth,"

VOA: standard.2010.01.13

And, seawater contains only 3.7% of the total magnesium present 7% in the Earth's crust.

而海水只含有,地表镁总量的,3。

麻省理工公开课 - 固态化学导论课程节选

I never knew bread could be this good; the crust was this dark brown, sweet crust that turned chewy in your mouth.

VOA: standard.2010.07.16