剑桥的官方真题可不便宜，动不动五、六十，七、八十一本，整个几套，再加上点听力、口语、语法、阅读、写作的专项训练，四、五百块到小一千，就花出去了。I used to be always forgetting what to variety for the above mentioned ssh-agent instructions, so I developed an alias in my .bashrc f