1. My sister is a bad-tempered person who would snap at anybody whenever she feels like it.2. Whenever I bring a guy to my apartment my roommate always snaps at him and asks him to leave.3. My sister may sound harsh when she criticizes you for doing wrong things, but she means well.
 bad-tempered snap at somebody sound harsh很多時候我們說恰北北是表示兇的意思，snap at 是動詞，表示一個人說話語氣又急又兇的意思，是恰北北很貼切的翻譯。
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 meting of glaciers, which leads to rising sea levels.