Use the Zero Conditional to talk about things that are generally or always true — scientific facts, rules, and predictable outcomes. If condition A happens, result B always happens.
Structure: If + Present Simple, Present Simple
Use the First Conditional to talk about a specific situation in the future and its likely result. It is a real possibility.
Structure: If + Present Simple, will/won't + base verb
Two very common words that work inside conditional sentences are when and unless. They each have a specific meaning and follow the same tense rules as if.
Besides if, when and unless, several other connectors work in Zero and First Conditional sentences. They all follow the same rule: Present Simple in the condition clause.
If you comply,
there will be no problem.
Provided that you comply,
there will be no problem.
Both conditionals use Present Simple in the if-clause, but the result clause is different. Compare them carefully!
| Feature | Zero Conditional | Structure | First Conditional |
|---|---|---|---|
| Meaning What is it for? |
Facts, rules, things that are always true | If + Pres. Simple, Pres. Simple | A real, possible future situation |
| Result clause | Present Simple | If + Pres. Simple, will + verb | will / won't + base verb |
| If ↔ When | Interchangeable — the result always happens | compare meaning | "When" shows certainty; "if" shows possibility |
| Example | If you heat ice, it melts. | If you heat the soup, it will taste better. | |
| Example | If staff are late, they receive a warning. | If you are late again, you will receive a warning. |
Welcome to the team! As the department manager, I oversee daily operations. It is my responsibility to ensure that all tasks are carried out efficiently. Let me explain a few basic rules. First, if you arrive after 9:00 AM, you must sign the late register. This is a strict rule: if an employee is late three times in a month, they receive a formal warning. Second, we are all accountable for our workspace. If you finish your shift, you must tidy your desk. Unless the office is kept clean, we will have to hire extra cleaning staff, which costs the company money. Finally, if you need time off, you will need to submit a form. If the form is approved by HR, you will receive an email confirmation within 24 hours. We expect everyone to comply with these guidelines.
1. What happens if an employee is late three times?
2. What is the consequence if the office is NOT kept clean?
3. According to the text, what is the manager's main responsibility?
Our company offers a flexible working-from-home policy, but every employee needs to understand the rules before they take advantage of it. As a general rule, if you want to work from home, you must ask your manager at least 24 hours in advance. Unless your manager approves the request, you cannot work remotely — this applies to everyone, no exceptions. If you work from home, you must still be online and available between 9:00 AM and 5:00 PM. When a colleague messages you during working hours, you should reply within 30 minutes, just as if you were in the office. Provided that you meet your deadlines, no one will check exactly how you organise your day. However, if you regularly miss deadlines while working remotely, your manager will review your access to the policy. As long as staff act responsibly, we are happy to keep offering this benefit. In case of a technical problem, contact IT immediately — they are always available to help, even on remote-working days.
1. What must you do before working from home?
2. What happens if you regularly miss deadlines while working remotely?
3. According to the text, when should you contact IT?
Opening a new office branch is a huge (1) [vocab]. As long as the budget (2) [zero/first cond.] approved on time, the renovation will begin next week. All safety procedures must (3) [modal + base verb] followed at all times during construction.
As the regional director, I am in (4) [vocab] of the project. If any problems (5) [zero cond.] during construction, they are dealt with immediately. Every Friday, provided that there (6) [provided that + pres. simple] progress to report, the site manager sends an update to headquarters.
We are hoping to open in two months. (7) [first cond.] we face severe weather problems, the opening ceremony (8) [first cond.] be held on May 1st. In case the weather (9) [in case + pres. simple] bad, we have booked an indoor venue as a backup.
When the office (10) [when + pres. simple] , new policies will be (11) [vocab] to ensure maximum efficiency. All staff will be held (12) [vocab] for their daily performance. If the supervisor (13) [zero cond.] tasks clearly each morning, the team works more efficiently. If staff do not (14) [zero cond.] with these rules, a warning is issued.
Check that both clauses use Present Simple — no "will" anywhere in a Zero Conditional sentence.
Check that the if-clause uses Present Simple (never "will"), and that the result clause has "will" for the future outcome.
Check for double negatives with "unless" ("unless...not") and remember: never use "will" straight after "when" or "unless".
Check that Present Simple (never "will") follows these connectors, and that "in case" is not confused with "if" (a precaution vs. a real condition).
Check whether the sentence describes a general fact/rule (Zero — Present Simple in both clauses) or a real future possibility (First — "will" in the result clause), and correct any mismatched tense.