重点讲解：
1. be unaware of 不知道的；不晓得的；未注意到的；
He was completely unaware of the whole affair.
他对整件事情一无所知RMN5E!lUP1Dv8X9J。
2. cross one's mind (想法)掠过心头，被想到，进入脑海；
It had never crossed his mind that there might be a problem.
他从未想过可能会有问题存在=0PR.6P9S7+kVH。
3. specialize in 专门从事；专门经营；专门研究；专攻；
He specialized in criminal law.
他专攻刑法ob=@_gDHh|_oU2(0;,Z。
4. in turn 继而；转而；反过来；
One of the members of the surgical team leaked the story to a fellow physician who, in turn, confided in a reporter.
手术小组的一名成员把这个消息泄露给了在一起工作的一个内科医生，后者又透露给了一位记者;%k6Dq.X2GOpSK9K。