距离2015年12月英语四六级考试还有一个月的时间，以下让我们一起回顾那些年我们学过的语法知识吧。
让步状语从句
常见的`连接词有though, although，as, while, even though
while：连接两个句子，表示虽然，但是;
eg：He is experienced while he is young.
区分though，although，as
eg：Although/though he is a child, he can live by himself.
as 表示虽然的时候，要进行倒装;
Child as/though he is , he can live by himself.
eg：Although/though she works very hard ,she makes very little progress.
Hard as she works, she makes very little progress.
Although/though she is young, she has travelled to many countries to put shows .
Young as she is, she has travelled to many countries to put shows .
真题分析：
anti-virus agent was not known until a doctor find it by chance.
(直到一名医生偶然发现了它)
2.I would prefer shopping online to shopping in a department store because __________(它更加方便和省时)it is more convenient and timesaving.
since water is much cheaper than wine, and many of the fancier brands aren’t available in stores, most diners don’t notice or care.
4. While there’s no question that continuous stress is harmful, several studies suggest that challenging situations in which you’re able to rise to the occasion can be good for you.
