查询词典 in the first instance

or your first and last：对你来说是很多个的第一个 还是第一个和最后一个

- I can't. - Okay. Tell me this.|- 我做不到 - 好... | Is Katy just your first, your first of many, or your first and last?|Katy对你来说是很多个的第一个 还是第一个和最后一个? | How should I know?|我怎么...

首先 first and last先后：first and foremost

far and near远近 | first and foremost首先 first and last先后 | free and easy轻松自在

first motion approximation：初动近似

初动 first motion, first movement | 初动近似 first motion approximation | 广义射线 generalized ray

first axiom of countability：第一可数性公理

first approximation 首次近似 | first axiom of countability 第一可数性公理 | first boundary condition 狄利克雷边界条件

first base：一垒的位置

first and foremost 首先 | first base 一垒的位置 | first baseman 一垒手

first base man：一垒手

first base一垒 | first base man一垒手 | first batter首位击球员

first base man：一垒员

first base man 一壘員 | first half 前半時 | first line center 前排中

first boundary condition：狄利克雷边界条件

first axiom of countability 第一可数性公理 | first boundary condition 狄利克雷边界条件 | first boundary value problem 狄利克雷问题

first boundary value problem：狄利克雷问题

first boundary condition 狄利克雷边界条件 | first boundary value problem 狄利克雷问题 | first class 第一类

first derivative spectrum：一级导数光谱

first derivative 一阶导数 | first derivative spectrum 一级导数光谱 | first derived curve 导曲线

necking：颈缩加工

marking 刻印加工 | necking 颈缩加工 | notching 冲口加工

nachfräsen re-mill, finish-mill：精铣,二道铣

Nachformschleifen copy-grinding, profile grinding, contour grinding 仿形磨削 | nachfräsen re-mill, finish-mill 精铣,二道铣 | nachgeschaltete Doppelkupplung two-stage double clutch 串接双离合器