To complete the sentences with the correct use of "if" or "when," we need to understand the difference between these two words in conditional sentences.
- If is used when the condition might happen or might not happen. It's often used in hypothetical situations.
- When is used when the condition is expected to happen as a matter of course.
Now, let’s fill in the sentences:
When she (gets up), she (will go) running with her dog.
- This describes a routine action, expected to occur when she gets up.
If people lived to be 100 in the UK, they (would receive) a letter from the Queen.
- This is a hypothetical situation because not everyone lives to be 100.
If the girl (feels) ill, she (will go) see a doctor.
- This is conditional and depends on the girl feeling ill.
If you (win), they (will organize) a party for you.
- This is conditional, contingent on you winning.
If he (has) to buy a car, he (will choose) a private class.
- The choice is dependent on the need to buy a car.
When you (see) him, you (will tell) Josh to be careful.
- This is something expected to happen when you see him.
If he (continues) eating indoors all the time, he (won’t be) very healthy.
- This is a conditional situation regarding his health.
When ice (melts), water (appears).
- This is a fact; it’s expected to happen as a natural result of ice melting.
If they (leave) it near the cooker, it (might catch) fire.
- This is a conditional situation of risk.
When she (can give) the letter to Susan, it (will be) read.
- This is an expected result when she can give the letter.
When you (put on) a raincoat, I can lend you an umbrella with me.
- This implies lending the umbrella is expected when they put on a raincoat.
If you (water) the garden often, it (will bloom).
- This is a condition for the garden to bloom.
Understanding these makes it easier to know when to use "if" (conditional, uncertain) and "when" (certain, expected).