I worried for fear that my friend would be hurt.
在这个句子里，for fear that起到连词的作用，引导一个目的状语从句。连词的作用就是起到连接的作用，可以连接词与词或句与句，它只是个虚词，不能担任句子成分。连词为数虽然不多，却很重要，有很多从句都由它来引导，例如主语从句、宾语从句、状语从句以及同位语从句等。从属连词引导从句，并列连词连接互不依从的词、短语或分句。
(1)She not only did the shopping but she also cooked the meal.
语法分析：并列连词not only...but also连接两个并列的成分，类似的并列连词还有either...or,neither...nor,both...and以及as well as 等。
(2)Slow but sure.
(3)Whenever she stayed home she went to bed early.
(4)He agreed to go and work there provided that his family could go with him.
语法分析：provided引导条件状语从句，起到连词作用，此外类似的还有if,unless,supposing,suppose,providing,as long as,in case等。
(5)Please don't try to back out now that everything has been arranged.
语法分析：now that引导原因状语从句，类似的连词还有seeing that,considering that,since,as以及because等。
(6)She's an honest girl even though I have opposed her.
语法分析：连词引导让步状语从句，除了even though,although,though,even if以及while等。
(1)I decided to play saft _____ for own sake and the job's.
(2)The cases were heavy,_____ we took a taxi.
(3)She raised the question _____ we ought to call in a specialist.
(4)I'll drive you _____ you're going.
(5)Arrange your hours _____ you like.
(6)He remembered the whole thing _____ it happened yesterday.
(7)He made _____ a noise that his sister tole him to be quiet.
(8)She was _____ fat that she couldn't get through the door.
(1)both (2)so (3)whether (4)where (5)whatever (6)as if (7)such (8)so