测量某地的海拔是以_______为起点计算的，在地图上把海洋中深度相同的各点连成线，叫做______线。
海平面；等深
What impressed the visitors deeply was ______ the workers made with their hands.
A．what
B．that
C．how
D．which
19，76，28，112，36，( )
A．114
B．124
C．134
D．144
