As fruit needs not only sunshine but cold nights and chillingshowers to ripen it, so character needs not only joy but trial anddifficulty to mellow it.
--Hugh Black, American writer
水果不仅需要阳光，也需要寒夜。寒冷的雨水能使其成熟。人的性格陶冶不仅需要欢乐，也需要考验和困难。
--休·布莱克(美国作家)

1. However, after a year or so in which they became more serious about their work,the Monkees started to play and sing theirown songs like a real band.
2.However, the next King of Prussia, Frederick William I ，to whom the amber room belonged, decided not to keep it.
3. Later, they may give performances in pubs or clubs, for which they are paid in cash.
4.They may start as a group of high school students,for whom practising their music in someone's house is the first step tofame.

(1)以上四个句子都使用了“介词＋关系代词”引导的定语从句。先行词若指物，那么介词后的关系代词用which;若指人，则用whom。
(2)以上四个句子中，句1是限制性定语从句，句2、3、4是非限制性定语从句。