บทที่17 - ที่เป็นเงื่อนไช (CONDITIONALS)

CONDITIONALS

A conditional sentence is made up of two parts: an if-clause and a main clause. When the if-clause comes before the main clause, the two clauses are separated with a comma. When the main clause comes before the if-clause, then no comma is necessary.

EXAMPLE: If Tom arrives early, we'll have dinner together. (If-clause comes before main clause. Comma required.)
EXAMPLE: We'll have dinner together if Tom arrives early. (Main clause comes before the if-clause. No comma required.)

There are three main types of conditional. They are commonly referred to as the first, second and third conditionals (or the Type 1, Type 2 or Type 3 conditionals.)

1. The First Conditional

The simple present tense is used in the if clause, and the tense in the main clause is the simple future tense. EXAMPLE: If you leave now, you'll arrive home early. 'If' Clause   Main Clause If + simple present tense   Simple future tense If you leave now,   you'll arrive home early. We can turn the two clauses the other way round so that their positions are reversed as follow: Simple future tense       if + simple present tense You'll arrive home early if you leave now.  Whether the if-clause or the main clause comes earlier, both conditional sentences as above are acceptable. With the first conditional, we use the present tense to talk about the future. We use this conditional when the situation in the if-clause appears likely and there is a possibility of it happening. EXAMPLE: If you help me with this, I'll buy you a drink. (You might help me) EXAMPLE: If I see him tomorrow, I'll tell him the good news. (I might see him tomorrow) The first conditional refers to the present condition that is real and a probable outcome. EXAMPLE: If the weather remains fine, we will go to the beach. EXAMPLE: If you continue to feel better, you will be out of the hospital soon. Going to can be used in the first conditional to refer to a future event. EXAMPLE: If she finishes work early, we are going to a restaurant for dinner. EXAMPLE: If you don't hurry, we are going to miss the train.

2. The Second Conditional

The simple past tense is used in the if clause, and the tense in the main clause is the present conditional. EXAMPLE: If he asked, we would explain everything. 'If' Clause   Main Clause If + simple past tense   would/could/might + infinitive (to have) If he asked,   we would explain everything  We can also let the main clause precede the if-clause, as follow: Would/could/might + infinitive (to have)   if + simple past tense We would explain everything if he asked. The second conditional refers to the present or future. We use Type 2 conditionals to describe: what is absolutely impossible. EXAMPLE: If your father were alive, he would be very proud of you. EXAMPLE: If I were younger, I would do things differently. Although the above two examples can use was instead of were as follow, the use of were is more formal. EXAMPLE: If your father was alive, he would be very proud of you. EXAMPLE: If I was younger, I would do things differently. a purely hypothetical situation. EXAMPLE: If I cooked like her, I would open a restaurant. (I can't cook like her.) EXAMPLE: If we earned more money, we would buy a bigger house. (We don't earn more money) unlikely events or not probable now. EXAMPLE: If she loved me, I would propose to her. (I don't think she loves me) EXAMPLE: If my parents restored their broken relationship, I'd* be very happy. (It's unlikely they will do that) imaginary situations that are unlikely to happen now or in the future. EXAMPLE: If I won the lottery, I would buy a luxury yacht EXAMPLE: If I married her, I would be the happiest man alive.

3. The Third  Condition

The past perfect tense is used in the if clause, and the tense in the main clause is the prefect conditional.  EXAMPLE: If you had planned what to do, you would have done it successfully. 'If' Clause Main Clause If + past perfect tense would/could/might + perfect infinitive (to have) If you had planned what to do    you would have done it successfully. The main clause can come before the if-clause, as follow: Would + perfect infinitive (to have) if + past perfect tense You would have done it successfully    if you had planned what to do Would expresses a desired or predictable result. could expresses a possible option. We use Type 3 conditionals to: express disappointment or regret about things that not possible to happen now. EXAMPLE: If I had married her, I could have been a happier person. EXAMPLE: If you had taken up teaching, you would have been better off. talk about things that should have happened in the past, but didn't. EXAMPLE: If you had requested information, the company would have provided it. EXAMPLE: If I had completed my education, I would have been somebody else today. imagine unrealistic situations EXAMPLE: If I had worked harder, I would have become a professor. EXAMPLE: If I had set up a business, I would have become very rich. express criticism. EXAMPLE: If he had got up earlier, he wouldn't have missed the bus. EXAMPLE: If she had been patient, she would have got what she wanted.