Would you correct my English?

"A boss who pretends to know anything lectures subordinates like a genius. However, if they take it as it is, they might end up failing."

...I'd go with "pretends to know everything", as I think everyone knows *something*. "Pretends to know anything" implies the boss knows nothing, but pretends to know something unspecified. You might try "take the advice at face value" or "take the advice as given" instead of "take it as it is", which implies getting by, doing well enough with something less than ideal (and here, you're suggesting they're not able to get by).

"Mr. Know-it-all type of bosses try to lecture us like they are always right. However, once you buy it, you could have a hard time." => "Know-it-all bosses try to lecture us like they are always right. However, if you buy it, you could have a hard time of it." (The "of it" is optional, but feels more natural to me.)

"Boss who pretends to know everything talks persistently as if he knows everything. However, if you follow his whole idea, you are going to be in a big trouble."

This third one's pretty good, but it needs to start with "A boss...". I'd change "his whole idea" to "his instructions word for word", or "exactly what he says".

"Mr.know-it-all speaks as if delivering a sermon to their subordinates. However, you might be in trouble if you just swallow it whole."

Again, pretty good... I'd go with "A know-it-all". "Mr. know-it-all" is usually only used when you're mocking someone in particular for acting like they know more than they do.

Bosses who pretend to know everything, lecture their subordinates like geniuses. However, if they take it as it is, they might end up failing.

Know-it-all type of bosses tries to lecture us like they are always right. However, once you buy it, you could have a hard time.

Bosses who pretend to know everything talk persistently as if they know everything. However, if you follow their whole idea, you are going to be in a big trouble.

Know-it-all bosses speak as if they are delivering a sermon to their subordinates. However, you may be in trouble if you just swallow it whole.

*All subjects above are changed to plural nouns to avoid clumsy pronoun he/she in latter clauses.

** Salutation like Mr, Miss and Ms are singular, I not sure if it adds up to the insult but for learning purposes try avoid cliche like Mr Nasty, Mr Rapist etc.

Good thing! My boss doesn't bark like yours.

A boss, who pretends to know everything, lectures subordinates like a genius. However, if they take it as it is they might end up failing.

Mr. Know-it-all types of bosses try to lecture us like they are always right. However, once you buy it, you could have a hard time.

The boss, who pretends to know everything, talks persistently as if he knows everything. However, if you follow his whole idea, you are going to be in big trouble.

"Mr. Know-it-all" speaks as if delivering a sermon to their subordinates. However, you might be in trouble if you swallow it whole.



They are good for the most part but there are little tiny things so look closely at what i did to every sentence! And if you are putting all these together somehow, remember not to use the word "however" this much. I noticed you used it a lot. Good luck with whatever this is doing for you! :)

The third one is incorrect. You would have to put "The" or "My" "Their" etc. in front of Boss or else it is considered a Fragment. After that is done you should correct it like this "___ Boss, whom pretends to know everything, talks persistently as if he knows everything. However, if you follow his whole idea, you are going to be in a big trouble"
Otherwise you are fine! :)