"If a person spent a lot of time on the internet complaining about the virtual world, they must be a loser in reality."

Dear Jingle: u really like using long sentense. If it did not offend, I tought u could try simple sentence at first. Then, using conjunction, such as and, but, or, moreover etc., combines two simple sentences. This is a good practice. Maybe, this kind of practice is too low to satisfy ur English level, but it's really important. Second, English is really different with Chinese. When we are talking one thing in Chinese, one word may cover many meanings. But, this is not the way how English speak. As your sentence, u use 'if' sentence which means a cause. But, when u ignore ",", it become hard to find inforamtion for effect. "If a person spent (<<verb is a signal) a lot of time on internet to complain the virtual world = cause who must be(<<signal 2) a loser in reality. = effect" Following the structure of 'if' sentence, "If a person (sl.) spent a lot of time on the internet complaining about the virtual world, he (sl.) would be a loser in reality." If + Subject + simple past, Subject+ should / would/ might/could + Verb...

Is it left?

no