矿体周围的岩石称为()。
参考答案:围岩
Last year the number of students who graduated with a driving licence reached 200,000, a(n) ______ of 40,000 per year.
A.average
B.number
C.amount
D.quantity
海啸主要是由浅源地震引起的,故又称地震波()
A.在外海其坡度甚小,很难观测到它
B.当其传至近岸时,因海水变浅,波高剧增,可达10米以上,最大25米
C.A.B都对
D.A.B都错