By the way, the infinitive without *to* is called the plain infinitive.

First off, the infinitive has no meaning aside from naming the action expressed by the verb. But it's unique in that it never refers to any specific person (=doesn't conjugate for person or tense), and can act like a noun: "To complain about the president would be considered treason in some countries." The only difference is in syntax: some grammatical forms require *to*: "I want/need/try *to* help." Other forms don't take it at all, like modal verbs: "I can, will, should –[to] go." And with some forms, it's optional: "This book will help (to) teach you English."

Also, in the second part, you could use WENT instead of SPENT and it would be way more natural!)))

It's perfect expect for the comma. You can't separate two full sentences with a comma. That's called a run-on sentence. You need a period (.) a semicolon (;) or an em-dash (—). But the meaning is very clear and natural. If you wrote this, I'm very impressed!

Your grammar and syntax are actually very good. The only thing I would point out is your pronunciation of /r/ and /d/. In many places you combine an American /r/ with a Spanish /r/ and the result sounds like two separate sounds. In Spanish, /r/ is just a simple tap. You say it perfectly in the word curiosidad. Also remember that /d/ between vowels is pronounced like English "th" in "this." No listen again to the beginning of your recording, the word **pudiera** has the wrong /d/ and an Americanized /r/. It should sound like [puð•yé•ɾa]. Also, you need to tighten up your vowels. The beauty of Spanish is that the vowels always sound exactly the same — they're all pure. Yet in some places you revert to the loose [ey] and [ou] of English, instead of pure [e] and [o]. Aside from that, congratulations on your brilliant Spanish! If you need me to illustrate these sounds, let me know and I'll set up a Zoom.

I don't understand the question.

Amirreza, if you translated this into your own language, I'm sure you would also use the word for "what." I used Google Translate here and I don't know Farsi, but this is what this quote means: اگر بیشتر مردم *آنچه* را که فکر می کنند می گفتند، حتی یک کلمه هم نمی گفتند.