重点讲解：
1. focus on
集中（注意力）；关注；
eg. I'd like you to focus on this project exclusively.
我希望你能把精力全放在这个项目上。
eg. We focus on the temporal objective.
我们专注于短期的目标。
2. concentrate on
全神贯注；集中（心思）；
eg. They will concentrate on teaching the basics of reading, writing and arithmetic.
他们将集中教授阅读、写作和算术基础知识。
eg. The group plans to concentrate on six core businesses.
该集团打算主营6种业务。
3. kind of
稍微；有几分；有点儿；
eg. She kind of hoped to be invited for her ex-boyfriend's wedding.
她有点儿希望被邀请参加前男友的婚礼。
eg. I've been feeling kind of blue lately.
我最近情绪有点儿低落。
