Children love stories. As evidence/As proof, they fall asleep while listening to music.
请问as proof, as evidence在此处用法正确吗？
中国人把as翻译为“作为”，采用翻译的方法，“作为证据，孩子喜欢边听故事边入睡”看起来没什么问题。
从语法角度，这里as后面跟noun (phrase)，修饰整个句子。The part of speech of as is connective or preposition.
Oxford English Dictionary有
9.
a. Introducing a clause modifying the whole main clause or some part other than its predicate: in accordance with what (is); in the way that.as men, things, etc., go: see go v. Phrases 3a(b).as a rule: see rule n.1 Phrases 1h. as usual: see usual adj. 4d.
11.
a. Introducing a noun phrase equivalent to a subject or object complement.
所以，as+noun phrase不能修饰整个句子。
至于as a girl，根据11，as可以引导修饰主语的名词，或宾语补语。
但是9a有例外，如as a rule, as usual。
总的来说，as在句子开头，只能引导修饰主语的名词，或某些固定搭配。