"You read as I write."
Translation:Tu lis alors que j'écris.
tu lis quand/lorsque j'écris: "when" is the best translation. Quand and lorsque are interchangeable as conjunctions, but only "quand" can start a question: quand lis-tu ?
Those conjunctions are as broad in meaning as "when".
tu lis pendant que j'écris: "while" is the best translation, plus the continuous tense that French does not have: you are reading while I am writing.
This conjunction implies a duration.
tu lis tandis que/alors que j'écris: "while" is one translation, but "whereas" can also be used, because of a dual meaning: duration or opposition.
I didn't find very much, but maybe these pages will help a little:
Alors que (At that time, While, even though)
Alors and Alors que have different meanings.
Tandis que also means while, whereas.
I felt it was good in a way that we hadn
t seentandis que
before now because it helped us to try and work out what the sentence structure would likely be; another example ofque
following another word in the conjunctive part of the sentence like withalors que` that could easily be forgotten without different examples of this happening.
Johan, In the examples you offer, "as" means while. Here is "as" used in a comparative way: the child's cheeks were as red as apples. You read as I write means just that. While (at the same time) you are reading, I am writing. I hope this is helpful. Your English is very good, no need to apologize.
It's better to separate these two in your mind. One is strictly a comparison of two things or people or x and y; nothing fancy or difficult about that. The other involves time: while (as) x was going out the door y was watching football. So the answer to your question is they are not always synonyms.