Sometimes you can use relative adverbs instead of relative pronoun + preposition. For example, the sentence: "The reason for which one person can become rich so fast in IT is a great accessibility to wide audience that IT can provide. can also be said like this: "The reason why one person can become rich so fast in IT is a great accessibility to wide audience IT can provide.
Restrictive relative clauses are parts of sentences or phrases that explain the first part and define the identity of a noun. While using this form, no commas are used. For example: "A consultant is a businessman whose job is to give advice to companies on how to use IT in the manner that will ensure maximum output with minimum investment."
You can sometimes omit the relative pronoun from the restrictive clause or form participle to make the sentence more fluent. For example, following sentence: "The briefing that was scheduled for tommorow is rumored to be very important." can also be said this way: "The briefing scheduled for tommorow is rumored to be very important." The sentences can only be shortened this way in sentences using restrictive relative clause.
Non-restrictive pronouns explain something, but don't define it. They are used when the identity of first part is already established. We can easily recognize them by commas, which are not part of restrictive relative clauses. The latter sentence is also an example of non-restrictive relative clauses. NOTICE: Relative pronoun "that" must not be used in sentences using non-restrictive pronouns.
Example: "This manager, who is typing something in his laptop, is one of our most succesfull workers."
Example: "The bosses, two of whom were very young, gathered at a public conference to discuss current trends in the industry."
Example: "My brother, whose old company went bankrupt, is starting a new business."
Example: "The company, that was thaught to produce only peripheral hardware, has released their first PPU card."
Example: "The IT servicing, in which your task is to maintain IT system of a company, is not a well pain job." Note that you can also shorten this sentence: "The IT servicing, where your task is to maintain IT system of a company, is not a well pain job."
Subject pronouns are detected if they are followed by a verb. For example: "Somebody responded to a post that was left on Moodle forum."
Object pronouns are recognized if they are not followed by a verb, but instead with a noun or a pronoun. For example: "Somebody responded to a post which you have left on Moodle forum."