horizontal gravity gradient

例句：

1. 1. The road ishorizontal to the north and south.
   这条路向北和向南都是水平的。
2. 2. The painting is horizontally hung on the wall.
   这幅画被水平挂在墙上。
3. 3. The car was horizontallyparked in front of the house.
   汽车被水平停放在房子前面。