The force of gravity makes things fall to earth.

地心引体落向地面。

It is gravitation that causes the apple to fall.

是地心吸引苹果下落。

The geotropism growth was a response of hypha to gravity and the geotropic sensitive was at the hyphal apex.

丛枝菌根真菌菌丝延伸生长部位是菌丝尖端，其生长的向地性是对地心引的应，应的敏部位也在生长菌丝的尖端。

This dissertation presents the theory and method on the establishment of height datums.And some problems on the geocenter motion are also studied.

本文系统地研究了建立高程基准的理论与方法、地心运动规律及其对高程基准的影响等有关问题。

Height is a measurement at right angles to this surface, and though gravity pulls mainly toward the centre of the earth, the geocentre, there are local variations.

高程是直于这表面的测度，而虽然重总是将体向地心方向拉，但局部总会有些变化。