又 vs. 再
Does anyone know the difference between 又 and 再?
Is 了 necessary in 我看到/见了你的新手机?
Disclaimer: Not a native speaker.
又 is for the past, and in some cases, used to emphasize something that's currently happening, it's the again of now and the past.
再 is for future iterations of something, an "again" for the future.
了 means that the action had a change in state, in a lot of cases, this translates to the past tense in English (but not all the time).
看 means to look or watch.
看到 means to see.
What is the result of looking or watching? It's seeing! You look at a bird or you watch a movie, and later you see both of them because your brain processed what you have looked or watched. Same thing goes with listening. What is the result of you listening to something? It's hearing that thing!
This is where 到 comes in. 到 is the result complement meaning that it is used to refer to the "result" of whatever verb you're talking about. When it comes to senses, it is the description of what happens after your brain processes what you sense.
了 has a complicated grammar. In your example, it can be interpreted as an action in the past tense but I personally give context like "yesterday, I verb 了 something“ to really emphasize if it is the past. In your example, 见了could just mean "I see your phone" rather than a more distant "I saw your phone". 看到 is more "in the moment" than 见了 but are not strictly past tense.
Read more about 了 usages: https://resources.allsetlearning.com/chinese/grammar/%E4%BA%86 Read more about result complements: https://resources.allsetlearning.com/chinese/grammar/Result_complement
- 你刚走怎么又来了？明天再来吧! you just leave why are you come again? come again tomorrow!
- 又来？你可不可以别再来了？ again? can you please not come again?
- 你怎么又生气了？再生气我就走了 Why are you being angry again? still angry again then I'll take my leave.
- 一次又一次，我再也不相信你了! again and again, I won't trust you anymore!
- 又下大雨~ 再这样下去可要淹水了.. Heavy rain again~ Keep go on like this then it may flooding..
- 我又还没醉， 再来一杯! I haven't drunk yet, one more glass!
- 再好看又怎样？ Even it is good looking then what?
- 又高又帅又体贴,我再也看不上其他男生了! tall,handsome, and thoughtful, I won't be able to fall for another man again!
Can you get some clue with those examples... XD