重点讲解：
1. pros and cons
利弊；优缺点；
eg. They sat for hours debating the pros and cons of setting up their own firm...
他们在一起坐了数小时，讨论自己创办公司的利弊。
eg. Motherhood has both its pros and cons.
当妈妈既有好的一面，也有不好的一面。
2. lack of
缺乏；不足；没有；
eg. There is a lack of people wanting to start up new businesses.
有创业意愿的人非常匮乏。
eg. He felt tired for lack of sleep.
他因缺少睡眠而感到疲劳。
3. confine to
限制，限定；
eg. Judges may be trained to confine themselves to the legally relevant facts before them.
法官接受的训练是将自己限制在面前的法律事实范围内。
eg. Wild animals are confined to cages.
野生动物被关在笼子里
