as long as | so long as | English grammar Both "as long as" and "so long as" can be used to give a condition. If you want A, you need B (the condition). A: You can borrow my car B (the condition): as long as you fill up the tank when you are done. The clauses can also be switched around: As long as you fill up the tank when you are done, you can borrow my car. A: My landlord says I can have a pet B (the condition): as long as it doesn't make too much noise. The clauses can also be switched aroun