You don't have to apologise, as this is not communicating somobody specific.

忙しのですから、

忙しかったので、is proper. When you talk about past, use past tense.

日本語を勉強しませんです。

日本語を勉強しませんでした。

Again, this should be past tense.

Even when you talk in present tense, しません is enough.

これから日本語を頑張りましょう。

これから日本語を頑張ります。

Because you are talking about yourself, this is better. This means "I will make effort to learn Japanese."

If you say 頑張りましょう, this is more like to encourage other people to learn Japanese.

そう、今日は文法を勉強します、

今日は文法を勉強します。

そう is an expression used in spoken Japanese. If you want say "so" then it could be "なので" or "だから".

そのルール多分、わかるけどチェックしてください。

???

If you use その、it is similar to when you use "the", meaning both you and the reader already know about the rule you're talking about. But I don't know which rule you are talking, then i got confused.

１．の 日本語を勉強するのは難しいんだ。

You dont need のhere. 難しいんだ could be OK, but more soiken word. You could use either 難しいです (more polite) or 難しい (totally acceptable in both written and spoken language)

ビールを飲むのはめんどくさい、明日は悪い感じのです。

We dont say めんどくさい for drinking beer. Do you want to say "i dont want to drink beer"? Then you could say 翌日調子が悪くなるので、ビールを飲みたくありません。 should be proper.

毎日勉強するのは、大変

Almost OK, but lets finish sentense with 。 or add です。

引っ越しのは難しいです。

I understand, but we don't use 難しい for moving. Proper words could be 大変です or めんどくさいです。

引越し is a noun so you dont need の.

２．と 日本語を勉強すると話そう

日本語を勉強すると話せるようになります。

Let's study how the verbs change their form.

話そう means lets talk.

話す talk

話せる can talk

This could be one of the difficulties non natives to learn.

皆は勉強しませんとゲームしません

Not really sure what you meant.

仕事を終わりと帰る

仕事が終わったら、帰ります。

I know work here is an object, but in Japnese we simetimes use object like subject.

I understand you already understand quite high level of Japanese. Keep learning! I'll keep learning English.

I'm also serious about learning English. I would be happy if you can be my language partner.

I live in Hong Kong since this August. I work in multi national environment now. While working in Japan, i was quite OK to communicate in emails, attend telephone conference, but after coming here I have some difficulties to communicate with my colleagus smoothly.

I would suggest to have a chat 1-2 times a week. My time 8:00 pm, your time 7:00 am. One hour earier or later is also pissible.

I would like you to point out what you don't understand when i speak, especially pronunciation errors.

I would also ge happy to help you for your japanese conversation.

Yoshiko

Good

いつか、ピアノで「Bohemian Rhapsody」を引けたい。弾けるようになりたい。//Someday I want to be able to play Bohemian Rhapsody on the piano.

近い将来友達のGonzoに合いたい。会いたい。// I will soon visit my friend Gonzo.

（if you use 「近い将来」, we feel there's some difficulty to meet Gonzo, either physical distance or any other. )

今戻りたいけど、もう帰りたいけど、近いうち

に すぐに教室をそうじしなきゃいけない　// I really wanna go home now, but I've gotta clean the class room [soon]

Instead of ten thousand (10,000), we have another unit "Man". Then 100,000 is Ju man (10 man).

Yes, pronanciation changes depending on what number comes before.

For instance;

100 Hyaku

300 San byaku

600 Roppyaku ( originally Roku hyaku)

Can't explain the logic for this. Sorry!