1. When our national security is at stake, we must do everything we can to restore peace.2. Working as a construction worker, he puts his safety in jeopardy every day.3. Working as a construction worker, he puts his safety at risk every day.
 at stake in jeopardy at risk這些片語都有「受到威脅」的意思，都是正統美語，非常好用。< >
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 chan 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 levels.