等高线是地面上高程相同的若干点所连成的（），或者说是（）与地表面相交曲线。
参考答案：光滑曲线；水平面
22. I _____ my university professor in the supermarket near my house, which was out of my expectation.
A．came out
B．came across
C．came about
D．came along
产后子宫复原可选用
A．垂体后叶素B．缩宫素C．加压素D．前列腺素E．麦角新碱
