水文现象的变化，如河道某一断面的水位、流量过程，常常具有某种程度的多年变化周期、年变化周期等。
参考答案：对
It was in the small house ________ was destroyed by the flood ________ he spent his childhood.
A．which; that
B．that; where
C．which; where
D．that; which
指出石英二长岩成因的正确说法（）。
A.变质形成的
B.沉积形成的
C.岩浆形成的
