A. Sample sentences
If interest rates fall, company profits rise.
If prices don't go up, people buy more.
If sales increase,we make more profit.
The sentences of Zero conditional are general facts or things that are always true, i.e. the consequence always follows the event. Statements in this form commonly appear in factual discussions or scientific and technical material.
In the condition clause there can be a variety of present forms. •When you fly business class, you get much more legroom. (present simple) •If interest rates are rising, bank loans become more expensive. (present continuous) •When you’ve finished the course, you get a certificate. (present perfect).
In the result clause there can be a present simple (last examples) or an imperative.
•When you fly business class, don’t drink too much of the free alcohol.
Notice that we can use either if or when(ever) where the meaning is every time.
A. Sample sentences
•If I do an MBA, I’ll improve my job prospects.
•If our main competitor goes bankrupt, we’ll increase our market share.
•If you increase your order,we’ll give you a bigger discount. •If anyone from Head Officesay I’m in a meeting.
1. In Conditional I the speaker sees the event as a real possibility, i.e., if-clause is used to talk about future events that are reasonably likely and their results. The if-clause states the condition, and the other clause states the result:
•If sales don't go well this year (condition), we won't increase our profits. (result)
With all types of conditionals the if-clause can come second. •We’ll make more profit if sales increase.
2. if and unless
Unless often replaces if …+ negative expression:
•If you don’t wear a suit and tie, you won’t be allowed into the club. •You won’t be allowed into the club unless you wear a suit and tie.
Conditional statements can function as either promises, warnings or threats. But note that unless cannot be used to make a promise. •If you order now, you’ll get a free gift. (promise)
•We won’t be able to do business with you unless you comply with our ethical policy. (warning) •Unless we receive payment by the end of the week we will be forced to consider legal action. (threat) CONDITIONAL I
3. In Conditional I, the imperative, or modal verbs can be used in the main clause, e.g. may, can or must, instead of will + infinitive:
•If you hear from Anne today, tell her to give me a call. •If the traffic is bad, I may miss the appointment with our supplier. •If we sign the contract today, we can start production at the end of next week. •If Mr. Porter rings, you must ask him to leave his number. CONDITIONAL I
4. We do not use will in the if part of the sentence even when the meaning is future: •If the goods will arrive tomorrow, I will collect it. () •If the goods arrive tomorrow, I will collect it. ()
Will is only possible in such cases if it is used to express not future time but willingness or invitations (the style is formal), e.g. •If you will sign this agreement, I will let you have the money at once. •If you will come this way, Mr. Jones will see you now.
5. In formal written documents, e.g. legal contracts or agreements, one may find the following conditional construction in Conditional I: •Should the agent default on the contract, we will take legal action. •Should the unions accept new productivity agreements, the employers will meet their wage demands. •Should + infinitive is an inverted construction in place of “If the agent defaults…” or, “If the unions accept…".
•!!!Note that only should, never would, is used in this way.