When I was checking in at the ticket counter, I had to pay $1500 extra for overweight luggage.
overweight luggage我的行李超重，被罰1500元 = I had to pay $1500 extra for overweight luggage.
這是一個連環問題: 燃燒石油導致二氧化碳增加，二氧化碳增加導致溫室效應，溫室效應導致冰層融化、海平面上升。 (請填空)
This is a chain of problems. Burning oil leads to increase in carbon dioxide, which leads to the greenhouse effect, which leads to melting of glciers, which leads to rising sea levels.