We should respect all kinds of people, including people of lower social class.
 people of lower social class people of lower social status這裡的低層指社會階層較低< >
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 glaciers, which leads to rising sea levls.