1. The ex-drug addict has relapsed and started doing drugs again.2. My husband, a recovering alcoholic, was sober for two years and he relapsed (into drinking) and went in for treatment for a month.3. His cancer came back. or His cancer returned.
 relapse come back returnrelapse 用在人後面，表示此人的舊的壞習慣(如毒癮)或舊的病情復發，通常 relapse 後面不加任何字，如 The ex-alcoholic relapsed.a recovering alcoholic = 一個正在戒除酒癮的人如要指某病復發，如癌症，可說 His cancer came back.
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 greehouse effect, which leads to melting of glaciers, which leads to rising sea levels.