Conditional mood (English) does not reflect real facts, but desired or hypothetical. Also, with its help, one can express a demand, doubt or condition, the fulfillment of which is associated with the possibility of realizing certain events.
The use and education of such forms in the English language is more complicated than in Russian, which uses only a “would” particle in front of the main verb.
Often this mood is confused with the subjunctive, but they represent phenomena that are different in meaning. Conditional mood (in English Conditional Mood), in contrast to the subjunctive, is used to denote such actions that have not occurred or do not occur, since there are no necessary conditions for this or they are not feasible in this situation, unrealistic. The subjunctive denotes unrealized conditions and expresses simply wishes or regrets.
There are two temporary forms of conditional mood: past and present.
Conditional present mood Conditional Present is formed using the auxiliary forms would / should and the infinitive of the main verb without "to". In other words, in form this inclination is identical to Future-in-the-Past.
Example: We would work . - We would work. In this case, the action expressed by the verb may occur in the present tense or future. Example: But for the bad weather we would work outdoors. - If it weren’t for the bad weather, we would work outside.
Conditional Past Leverage Conditional Past expresses an action that, under certain conditions, could have taken place in the past, but failed because of the absence of these conditions. Formed by should have and would have and the main verb in the third form (identical to Future Perfect-in-the-Past).
Example: She would have purchased a dress but the store was closed. - She would have bought a dress if the store had not been closed
As a rule, conditional mood is used in complex subordinate conditional sentences, less common in simple ones. In the subordinate clause of a complex sentence, the condition is called, and in the main, the consequence (result) is expressed. Both of these parts can relate to the present, and to the past or future. Most often, parts of a complex sentence are linked by a union if ( if). Separate the sentence with a comma only if the subordinate clause is in front of the main one.
There are three types of conditional sentences. They express different degrees of probability of the described facts. The choice of type of sentence is determined by the speaker's attitude to what is being said.
A type I - events real
If such sentences are about real events, then conditional mood is not used, it is quite successfully replaced by the indicative.
Example: If I have more money, I will by an expensive car. “If I have more money, I will buy an expensive car.”
Grammatically, the main sentence uses the time Simple future - Future Simple, and the subordinate - the simple present - Present Simple.
The first type can also express unlikely events, the reality of which is much lower than in the previous case.
Example: If I should have more money, I will purchase a car. - If I had more money, I would buy a car. (It is understood that at this time the money is not enough to buy a car, but they can be accumulated and fulfill the desired).
Future Simple is used in the main sentence, should + infinitive in the subordinate clause.
A type II - unlikely, almost real events
The speaker does not consider what he reports as a real event, but simply assumes what could have happened under a certain set of circumstances.
Example: If he had money, he would purchase a car. - If he suddenly had a sufficient amount of money, he would have bought a car. (There was no purchase, but if a random inheritance had fallen on his head, he could have bought a car.)
In the main part would be used + infinitive, in the subordinate - Past Simple.
A type III - completely, absolutely unrealistic events
Expresses wishes (often regrets) regarding the past, in which nothing is already impossible to change.
Example: If he had had money, he would have purchase a car 2 years ago. - If he had money then, he would have bought a car already two years ago. (But did not buy, because there was no money).
The main sentence would use a perfect infinitive +, in the subordinate - forms that have verbs (English) in Past Perfect tense.