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unless until
unless与until均为从属连词,unless表"除非",强调条件,引导条件状语从句;until表"直到",强调时间的延续,引导时间状语从句。
1)I didn't know the news until my teacher told it to me.
2)I couldn't know the news unless my teacher told it to me.
3)-Was his father very strict with him when he was at school?
-Yes. He had never praised him until he became one of the top students in his grade.
析:句1动词didn't know表明该句强调时间的延续,表"我不知道这消息"的状态一直延续到"老师告诉我",因此应用until引导时间状语从句。句2动词couldn't know表明该句强调条件,表"我不可能知道这消息,除非老师告诉我",因此应用unless引导条件状语从句。句3表明"他爸爸从来没有表扬他"的状态一直延续到"他变成年级最好的学生之一",因此也应用until引导时间状语从句。
2.On behalf of the American people, we're frustrated by the remarks.
on behalf of为了…的利益
例句：He spoke on behalf of the plan.
他为这项计划辩护。
代表…
例句：At the airport he read an address of welcome on behalf of the association.
在机场上他代表该协会致了欢迎词。
