大学英语四级考试的常用语法精选（12）

　　表示因果: for, so, therefore, hence 　　从属连词 　　表示时间: when, while, as, after, before, since, until, as soon as, once 　　表示原因: because, as, since, now that, seeing that 　　表示条件: if, unless, in case, provided, suppose, as long as, on condition , 　　表示其他关系: though, than, as 　　My father, who had been on a visit to America, returned yesterday. 　　All the books, which had pictures in them, were sent to the little girl. 　　定语从句的引导词 　　that, who, whom: 非限制性定语从句, 如果修饰人, 一般用who, 有时用that . 如果关系代词在从句中作宾语, 就应当用宾格 whom 或that, 但在大多数情况下都可以省略掉, 在口语中可用who代替whom. 　　Here is the man youve been looking for. 　　He is a man you can safely depend on. 　　The people I spoke to is my cousin. 　　限制性定语从句如果修饰物, 用关系代词that的时候较多, 也有时用which.. 当这个代词在从句中是用作宾语时, 在绝大多数情况下都是省略的, 特别是口语中: 　　Have you everything you need? 　　anything I can do for you? 　　All you have to do is to press the button.