關於英文the number one thing to remember is後接動詞的問題。?

原句採用省略了to的bare infinitive，是否合文法會有爭議，但不是完全沒來由。

1.) 首先為便於理解，先簡化句子
The number one thing to remember is never (to) run away. 採用不定詞 "to run"，是最沒爭議。但有些母語人士碰到這種 "reversible specifying construction" 句型，往往會省去to。

2.) reversible specifying construction
[The number one thing to remember] is [never (to) run away.] = [Noun Phrase] + be + [predicative complement]

這種句型be前作為主詞的名詞片語，和be後的述部補語是可互換位置，意思還是不變。例如

i) His intention was {for the meeting) to begin at six. [to-infinitival]
= (For the meeting) to begin at six was his intention.

ii) The funniest thing was (Kim) trying to hide in the coal-box, [gerund-participial]
= (Kim's) trying to hide in the coal-box was the funniest thing.

iii) All I did was print out the table of contents. [bare infinitival]
= To print out the table of contents was all I did. (這時to不可省去)
當作為主詞的noun phrase 或 what-clause 的主要動詞為do時，述部補語可採用bare infinitive

(之前，有一類似問題，我怕發問者容易困惑，刻意不談 reversible specifying construction
https://tw.answers.yahoo.com/question/index?qid=20170912152233AA86QUm

3.) 原句可採下列寫法
The number one thing to remember is that you never run away. ( you 不可省)
The number one thing to remember is never to run away.

原句=
The number one thing ...is (that you) never, ever run away unless you want the dog to run after you.

是 (that you) 被省略掉了.

簡單先不要把run away看成是動詞(run)來研究/討論，因為主題是one thing是指出一個"名詞"性的東西，就算這東西是"要做/不做"的事，從文意/文法上寫出來是"名詞"子句/片意

因此'run away', 'stop', 'don't move', 'look away', 'turn aside', 'back up'等等看似行動指示的片語都不是"動詞"或"分詞"，因為這句的句性是指示而不是講故事/敘事/描寫文.