练习说明：
周一到周五是16个单词 + 一段翻译（单词做到认识就好，快速记忆多次重复。翻译关注紫色部分的表达，可以进行互译检测：看到中文回忆英文，看到英文回忆中文）
周六真题及其详解，再次巩固词汇体会完形题目
周日文章结构图，可以对照之前的翻译练习再次巩固
前期大家可以多关注单词。
The idea is to create a federation of private online identity systems. Users could select which system to join, and only registered users whose identities have been authenticated could navigate those systems. The approach contrasts with one that would require an Internet driver’s license issued by the government.
Google and Microsoft are among companies that already have these “single sign-on” systems that make it possible for users to log in just once but use many different services.
今日句子分析1：
The approach contrasts with one that would require an Internet driver’s license issued by the government.
这里面主句就是用了A contrasts with B这个短语，所以主干就是The approach contrasts with one 这种方式与另一种（方式）明显不同。那另一种方式是什么呢？所以用that引导一个定语从句进行解释说明。
今日句子分析2：
Google and Microsoft are among companies that already have these “single sign-on” systems that make it possible for users to log in just once but use many different services.
大家只需要注意后面systems that make it possible for users to log in just once but use many different services. 这里的it做形式宾语，其后的不定式是真正的宾语，possible做宾语补足语。
这种结构在英语中很常见，例如：
I think it is convenient to come at two. 我认为两点钟来较适合。
George made it clear what he wanted. 乔治说得很明白他要什么。
