Zero and First Conditional: General Truths and Future Possibilities
Let’s start by looking at the zero conditional and first conditional by looking at the following example:
(1) If / When ice is heated, it melts.
(2) If we don’t do something about climate change soon, ice caps will melt and polar bears will eventually become extinct.
The first sentence above is an example of the zero conditional which is used to talk about general facts or constant truths. Both clauses contain the present simple and the condition clause can be started with if or when.
As with all conditionals, the two clauses can go in any order. However, it is important to note that, if the condition clause goes first, it must be followed by a comma. The same is not true if we write the sentence the other way around.
For example: If ice is heated, it melts or Ice melts if it is heated.
The following exercise contains further examples of the zero conditional. Match the two halves of the sentences.
Having done the above, let’s now look more closely at the first conditional which is used to talk about real future possibility. Similar to the zero conditional, the condition clause is in the present simple. However, the consequence clause uses a future tense. This can be will, going to, or shall.
For example: If I’m able to retire next year, I’m going to have a huge party or I’ll/shall be very happy if I pass the exam.
As we are using the first conditional to talk about the future, it uses the same structure as other future clauses preceded by conjunctions, such as before / after / as soon as / unless / until.
In the following exercise, choose the correct tense form for each clause bearing in mind the rules above.
Now try the following by dragging the correct adverb into the boxes.
Task Tips
Two adverbs which are commonly misused at C1 level are until and unless.
If something happens until a particular time, it means that it continues to and stops at that point.
For example: I ate meat until I was 18 but have been a vegetarian since then or I'll be stuck at work until I get this work done.
Unless is used to say that something will happen or is true if something else does not happen or isn't true.
For example: The boss says I can't have a few days off unless I get this project done.