I'm attempting to teach "connecting prepositions (If, when, as long as)" to my students. In order to be successful, I need to come up with examples using phrases instead of full clauses; otherwise, they would be subordinating conjunctions.

For example, these are easy for me to think up but not what I need:

• If you loan me your eraser, I'll be your best friend forever. (subordinating conjunction)
• When class is over, you need to return it. (subordinating conjunction)
• You may borrow my laptop as long as you take care of it. (subordinating conjunction)

These are what I need an abundance of but am struggling to come up with:

• If you're able to come, I'll sit with you. (conjunction) If not, I'll sit by myself. (preposition)
• It will last a long time when correctly used. (preposition)
• I'll keep on trying as long as possible. (preposition)

Do you know a source where I could access ready-to-go examples? Or can you help me create more examples? I'm looking for examples of connecting prepositions, specifically using "if," "when" and "as long as." Thank you!