The cleaning crew leader of a class is responsible for keeping in contact with the local authority when classmates are infected with a disease. He or she is also responsible for promoting the knowledge of health and hygiene.
Cleaning crew leader此為白話翻譯，因為美國的 class 通常指一整個年級，如 Class of 2014，而不是台灣學校的一個小班級。
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 efect, which leads to melting of glaciers, which leads to rising sea levels.