Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
cache - n. a group of things that have been hidden in a secret place
attorney - n. lawyer
assert - v. to state something strongly
geophysical - adj. relating to the physics of the earth
speculation - n. ideas or guesses about something that is not known
to the contrary - phrase. stating or proving the opposite of something
excavation - n. dig
