保证铁路无缝线路冬天钢轨不被拉断、夏天不发生胀轨跑道的轨温为()轨温。
A.零应力
B.中间
C.设计锁定
D.施工锁定
参考答案:C
Was it in the beautiful park ______was located by the sea _____ you first met your new English teacher? [ ]
A. where; that
B. which; which
C. that; that
D. which; where
简述牙的演化规律。