1．You could get into a situation ________ you have to decide immediately.
答案：where 设空处所填词引导定语从句，先行词为situation，从句中不缺少主语和宾语，situation “处境”，是表示抽象地点概念的先行词，关系词在从句中作状语，表地点，因此填where。
2．I am having trouble ________ the new computer, but I don't know ________ to turn to.
答案：with；whom 第一空为短语have trouble with sth. “某物出了问题”；第二空由句意可知表示向谁求助，作介词to的宾语，应用whom。
3．The reason _______ the injection needs repeating every year is that the virus changes.
答案：why 空格处所填词在本句中引导定语从句，修饰先行词the reason，关系词在从句中作状语，表原因，故填why。句意：注射需要每年重复的原因是病毒总在改变。
4．Internet crime is a subject ________ the world might argue for a long while.
答案：about which 此处为“介词＋关系代词”引导的定语从句，根据定语从句的动词短语argue about “争论……”可知，介词应填about；先行词a subject表示物，关系代词用which。
5．It was a prison ________ which no one escaped.
答案：from 此处为“介词＋关系代词”引导的定语从句，根据定语从句的动词短语escape from “从……逃脱”可知，介词应填from；先行词为prison，表示物，关系代词用which。
