Explain the concept of 'relative clauses of condition' and provide examples.

Relative clauses of condition are a type of subordinate clause that provide additional information about a condition or circumstance that must be met for the main clause to occur. These clauses are introduced by relative pronouns such as "if," "unless," "provided that," "in case," or "whether."

Relative clauses of condition can be used to express hypothetical situations, possibilities, or requirements. They help to add complexity and specificity to a sentence by providing more details about the condition under which the main clause will happen.

Here are some examples of relative clauses of condition:

1. If it rains, we will stay indoors.
- In this example, the relative clause "if it rains" introduces the condition that must be met for the main clause "we will stay indoors" to occur. It implies that staying indoors is dependent on the occurrence of rain.

2. I will go to the party unless I have to work late.
- The relative clause "unless I have to work late" introduces the condition that must not be met for the main clause "I will go to the party" to happen. It suggests that attending the party is contingent on not having to work late.

3. You can borrow my car provided that you return it by tomorrow.
- In this example, the relative clause "provided that you return it by tomorrow" sets the condition that must be fulfilled for the main clause "you can borrow my car" to be valid. It indicates that borrowing the car is subject to the condition of returning it by tomorrow.

4. Take an umbrella in case it starts raining.
- The relative clause "in case it starts raining" introduces the condition that should be anticipated for the main clause "take an umbrella" to be necessary. It suggests that taking an umbrella is advisable in anticipation of potential rain.

5. I don't know whether she will come or not.
- The relative clause "whether she will come or not" introduces the condition of uncertainty regarding the main clause "I don't know." It implies that the speaker is unsure about whether she will come or not.

In summary, relative clauses of condition provide additional information about the conditions or circumstances that must be met for the main clause to occur. They are introduced by relative pronouns and help to add complexity and specificity to sentences by expressing hypothetical situations, possibilities, or requirements.