When surveyors sight the summit, there is a risk they might not all measure the same point.
当测量员们看到山顶时，他们可能无法测量到同一个点。
2
To measure the difference in elevation between poles, surveyors used an optical level—a telescope on a level base—placed halfway between the poles.
为了测量两极之间的高程差，测量员在两极中间的一个水平基座上使用了光学水准望远镜。
3
The companies building the canals to transport coal needed surveyors to help them find the coal deposits worth mining as well as to determine the best courses for the canals.