The rainy season is coming in Shanghai | to Shanghai. The rainy season is coming in Shanghai | to Shanghai.

My tomato plants have thirty fruits nowproduced 30 tomatoes now./I've now grown 30 tomatoes. My tomato plants have produced 30 tomatoes now./I've now grown 30 tomatoes.

There is no plural for "fruit" and we don't use it as a countable noun.

My tomato plants have thirty {fruits | tomatoes} now. My tomato plants have thirty {fruits | tomatoes} now.

“Fruits” isn’t idiomatic here for me, but it might be to some native English speakers.

My tomato plants have thirty fruits now. My tomato plants have thirty fruits now.

Maybe it'sthese are the final numbertomatoes because it's said that tomato plants have a hard time surviving in the rainy season. Maybe these are the final tomatoes because it's said that tomato plants have a hard time surviving in the rainy season.

Maybe {it's | it will turn out to be} the final number because it's said that tomato plants have a hard time surviving in the rainy season. Maybe {it's | it will turn out to be} the final number because it's said that tomato plants have a hard time surviving in the rainy season.

I'll try to keep all thirty aliveviable until ripe | until they ripen. I'll try to keep all thirty viable until ripe | until they ripen.

I don’t think we say that fruit is “alive” even when it’s still growing, but I might be wrong.

I'll try to keep all thirty alivehealthy until ripe. I'll try to keep all thirty healthy until ripe.

Alive is understandable but a bit strange to the English ear.

And for the same reason, I bought a small set for Xiaojuzikit/device to increase the water's oxygen level. And for the same reason, I bought a small kit/device to increase the water's oxygen level.

Could you explain what Xiaojuzi is? That might allow me to give a better translation.

And for the same reason, I bought a small setdevice for Xiaojuzi to increase the water's oxygen level. And for the same reason, I bought a small device for Xiaojuzi to increase the water's oxygen level.

And for the same reason, I bought a small set [? of what?] for Xiaojuzi to increase the water's oxygen level. And for the same reason, I bought a small set [? of what?] for Xiaojuzi to increase the water's oxygen level.

I didn't understanding your meaning here.

And fFor the same reason, I bought a small setdevice for Xiaojuzi, my betta fish, to increase the water's oxygen level. For the same reason, I bought a small device for Xiaojuzi, my betta fish, to increase the water's oxygen level.

I removed 'And' here as you don't really need it, and you repeat 'And' quite a few times. I saw your comment about 小橘子 so corrected based on that. I had a quick look online and, generally, we would refer to these as a 'device' rather than a 'set' (I don't have any fish myself so I wasn't too sure).

Recently, I have found it quite interesting to reply to questions from other people in English on social media. Recently, I have found it quite interesting to reply to questions from other people in English on social media

Recently, I have found it quite interesting to reply to questions from other people in English on social media., especially… Recently, I have found it quite interesting to reply to questions from other people in English on social media, especially…

E, especially regarding the issues that I'm familiar with. , especially regarding the issues that I'm familiar with.

Eespecially regarding the issues that I'm familiar with. especially regarding issues that I'm familiar with.

Especially regarding the issues thatwith which I'm familiar with. Especially regarding the issues with which I'm familiar.

You're text is normal and oft-used, and is fine on the modern view (modern language guides would say its fine), but the above is sometimes used in formal contexts or in more stuffy writing. So not a correction, just an edit in a different, more formal register. English used to have a rule of not ending sentences with prepositions so in grade school you might get the above as a "correction".

Someone asked about Chinese tea, and I replied with the following: Someone asked about Chinese tea, and I replied with the following:

Someone asked about Chinese tea, and I replied (with) the following: Someone asked about Chinese tea, and I replied (with) the following:

It's a great place | They’re great places to relax and chat, where you can order and enjoy some amazing tea. It's a great place | They’re great places to relax and chat, where you can order and enjoy some amazing tea.

“It’s” feels unnatural to me because you’re not referring to a specific tea house, you’re referring to tea houses in general. Using the plural feels more natural to me.

It's a great place to relax and chat, where you can order and enjoy some amazing tea. It's a great place to relax and chat, where you can order and enjoy some amazing tea.

Using "it's" is fine here! You're referring to a collective noun, which is singular.

I'd like to show you guys the birds presentthat live in my small garden. I'd like to show you guys the birds that live in my small garden.

Present is fine for meaning and gramatically but a little strange to the ear in this context.

The leaves of my perilla and mugwort {have almost all been | have been almost completely} eaten up by them. The leaves of my perilla and mugwort {have almost all been | have been almost completely} eaten up by them.