前(まえ)にBefore, In front of

あとで and まえに are both used to describe the timing of actions, but with opposite meanings. まえに usually follows a plain (non-past) verb and means 'before doing A' (e.g., 食べる前に = 'before eating'). In contrast, あとで typically follows the past tense form of a verb and means 'after doing B' (e.g., 食べたあとで = 'after eating').

ないうちに and まえに both mean doing something before another event, but with different nuances. まえに simply marks one action happening before another. ないうちに adds the sense of doing something while there's still time. For example, 暗くならないうちに帰ろう means 'Let's go home before it gets dark,' with the nuance that it's better to leave while it's still light out.

まえに is used to express the relative timing of actions and often follows a plain (non-past) verb to mean 'before doing A.' In contrast, 前者 (the former) and 後者 (the latter) refer to things previously mentioned. They're used to avoid repeating a word or phrase, similar to how we use 'the former' and 'the latter' in English.

Both まえに and 手前 can express a meaning similar to ''before' or 'in front of' in English. The difference is that まえに simply refers to happening earlier in time, or being physically located in front of something else. In contrast, 手前 adds nuance, often implying that, because one is faced with a certain situation (A), a particular action or outcome (B) follows as a result.