§ 145. Complex sentences with a subordinate clause of condi- tion (conditional sentences)1 may be divided into two groups: sen- tences of real condition and sentences of unreal condition.

¹ In conditional sentences forms expressing unreality are used in both the princi- pal clause and in the subordinate clause (the if-clause), whereas in all the previously described types of sentences forms expressing unreality are found only in subordinate clauses.

In sentences of real condition we find the Indicative Mood. They usually refer to the future, so the Future tense is used in the principal clause and the present tense in the if-clause.

e.g. If you continue in this way you'll break your mother's heart. You won't be believed if you tell the truth.

Sentences of real condition may also refer to the present or past, though not very often.

e.g. I always lose money if I bet.

In the evenings we played chess or strolled about if it was

fine.

It should be noted that sentences of the latter kind express regularly occurring actions.

Clauses of condition are usually joined to the principal clause by means of the conjunction if and are therefore called if-clauses. There are other conjunctions which serve to introduce clauses of condition, but their use is not so common. They are: unless, in case, supposing (suppose) that, providing (provided) that, on condi tion that.

Note. If has the most general meaning of all the conjunctions introducing clauses of condition. Its use is not restricted in any way, whereas all the other conjunctions are limited in their application either for semantic or stylistic rea- sons. Roughly unless means 'if...not'. However, there is a difference between them: unless has the more exclusive meaning of 'only if... not' or 'except on con- dition that'. The most adequate way of rendering this conjunction in Russian is если только не.

e.g. We never part with things, you know, unless we want something in their place. "Does the professor know?" "No. And he won't unless it is absolutely neces- sary."

While if ... not can be used instead of unless, though the clause will be de- prived of the above mentioned specific shade of meaning, unless cannot always serve as a substitute for if ... not. For example, unless cannot be used in the follow- ing sentence: e.g. If your wife doesn't like the ring, I'll be happy to exchange it any time.

In case also has a specific shade of meaning implying purpose as well as condi- tion. It should be rendered in Russian as на mоm случай, если.

e.g. I'd like the doctor handy in case she feels worse.

I've made provision in case anything happens to me.

Supposing (that) and suppose (that) preserve the meaning of supposition as their origin from the verb to suppose is still strongly felt. They are best of all ren- dered in Russian by means of предположим and are found in the following kinds of sentences:

e.g. Suppose he doesn't turn up, what shall we do?

What will his uncle think of him, supposing it's true?

Providing (that) and provided (that) are rather narrow in meaning indicating a favourable and desirable condition, which is explained by their connection with the verb to provide. Besides, they are rather formal stylistically, being more typical of official documents. The closest Russian equivalents are если, при наличии, при условии.

e.g. But so long as a Forsyte got what he was after, he was not too particular about

the means, provided appearances were saved.

We are prepared to sign the agreement providing that you guarantee the high quality of the goods.

On condition (that) is also connected with its original meaning (при условии) and at the same time it is restricted stylistically, being more formal than if.

e.g. I will agree to this year's budget on condition that we drop this foreign busi- ness in future.

All these conjunctions may be used in sentences of both real and unreal condition.

§ 146. In sentences of unreal condition we find forms express- ing unreality: the form of the Past Indefinite or the Past Perfect is used in the if-clause, and the Conditional Mood (Present and Past) is used in the principal clause.

The action of the if-clause is represented by the speaker as con- tradicting reality; consequently the action of the principal clause, which depends on this unreal condition, cannot be realized either.

When a sentence of unreal condition refers to the present or future, the form of the Past Indefinite is used in the if-clause and the Present Conditional Mood in the principal clause.

e.g. How nice it would be for Mother if we had a car.

You ought to know your uncle by this time. He's just like a

child. He'd be a pauper tomorrow if I didn't see to things. If the hospital were not so overcrowded, he said, he would

recommend that she should be taken there.

When a sentence of unreal condition refers to the past, we find the form of the Past Perfect in the if-clause and the Past Conditional Mood in the principal clause.

e.g. It would have been too wonderful if he had said that. But he

didn't. Of course, all this wouldn't have happened if the girl hadn't

been so excited. I should have been sorry if I hadn't spoken.