水准测量原理 The Principle of Leveling 水准仪及其使用 The Water Level and the Usage 水准测量的一般方法和要求 The Common Methods and Demand of the Water Level 水准仪的检验和校正 The Inspection and Emendation of the Water Level 水准测量误差产生的原因及消减方法 The Causes and Elimination of Leveling
set off, set out这两个短语动词都有“出发”和“动身”的意思 ,都可以解释为 start to move或 begin journey. 然而 set off的原义是使爆炸(cause to explode) set out的原义是着手做(begin work with the intention of achieving a particular aim). 注: set out在用来表示“着手做”(begin with definite purpose) 时,后面总是跟动词不定式