Presentation on theme: "Conditional Sentences If vs Unless * When and How to use them *"— Presentation transcript:
Conditional Sentences If vs Unless * When and How to use them *
Introduction Conditional sentences have two parts: Cause Effect / Action Both If and Unless are possible. There are four kinds of conditional sentences. One of them is an exception (type 0). If-clause / unless Every type is composed of Main-clause It doesn’t matter which comes first: I’ll get a good mark, if I learn my vocabulary. If I learn my vocabulary, I’ll get a good mark.
Type 0 If-clause Simple present Main-clause If you freeze water, it becomes a solid. Plants die, if you don’t water them. If you mix blue and yellow, you get green. It comes from oral language and it has a very definite meaning; In this conditional, the time is now or always; This type of sentence implies that the situation is real, possible or inevitable.
Type I If-clause – Present Simple Main-clause – Future (Will + Infinitive) If I learn my vocabulary, I`ll get a good mark. The if-clause usually indicates a real or possible situation that can happen in the present or in the future. It is possible and also very probable that the condition will be fulfilled.
Type II If-clause – Past simple Main-clause – Conditional (Would + Infinitive) If I learnt my vocabulary, I would get a good mark. Type II is used when a condition is less probable to happen than in Type I Example: Will Mary be in time if she gets the ten o’clock bus? (Type I) No, but she would be in time if she got the nine bus. (Type II)
Type II When we don’t expect the action in the if-clause to take place: Example: If burglar came into my room at night, I would throw something at him. (Meaning, I don´t expect a burglar to come in.) When the supposition is contrary to known facts: Example: If I had a map, I would lend it to you. (But I haven’t got a map. ) It is possible but very unlikely, that the condition will be fulfilled.
Type III If-clause – Past perfect Main-clause – Conditional Perfect [would (not) have + past participle] If I had known that you were coming, I would have met you at the airport. (But I didn’t know so I didn’t went.) NOTE: Both would and had can be contracted to ‘d. You never use would in the IF-clause. Example: “If I’d known” “If I had known“, “I’d have baked” “I would have baked..” It is impossible that the condition will ever be fulfilled because it refers to the past.
Unless Unless means the same as if … not. Like if, it is followed by a present, a past or a past perfect tense. It is used instead of if + not in conditional tenses of all types: It is used to emphasize an idea or action. Type I (Unless + Present Simple) You will never understand English, unless you study this grammar carefully. (= You will never understand English if you don’t study this grammar carefully)
Unless Type II (Unless + Past Simple) Unless he was very hill, he would be at work. (= If he wasn’t very hill, he would be at work) Type III (Unless + Past Perfect) I wouldn’t have phoned him, unless you had suggested it. (= I wouldn’t have phoned him, if you hadn’t suggested it) Your Teacher: António Andrade