题目

While income worry is a rather common problem of the ahead, loneliness is another problem that aged parents may face．Of all the reasons that explain their loneliness, a large geographical distance between parents and their children is the major one．This phenomenon（现象） is commonly known as “Empty Nest Syndrome”. In order to seek better chances outside their countries, many young people have gone abroad, leaving their parents behind with no clear idea of when they will return home．Their parents spend countless lonely days and nights, taking care of themselves, in the hope that Jack had traveled six miles across the Channel ______ his engine failed and was forced to land on the sea. 　 A. when　　 B. until C. after　　 D. since