1. Even though I am old, I still want my mom around after I fall and skin my knee in front of a bunch of strangers.2. When the car hit her bicycle, she was lucky to only get a scrape on her knee.3. The ointment is for scrapes.4. I scraped my knee when I fell.
 skin scrape graze scratch abrasionskin 常用在擦傷膝蓋，有可能流血也有可能只是紅紅的。她擦傷了自己的膝蓋 = She skinned her knee.scrape 跟 graze 都比 scratch 嚴重，scrape 是擦傷的最常用的英文之一，可當動詞或名詞。我的膝蓋有個擦傷 = I got a scrape on my knee.
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 grenhouse effect, which leads to melting of glaciers, which leads to rising sea levels.