重点讲解：
1. work-out
体育锻炼；体育训练；
eg. Give your upper body a work-out by using handweights.
用哑铃来锻炼上身。
2. work on
从事于…；忙于；
eg. Leaders ought to work on sanctioning unethical behavior before it gets to a level that regulators would flag. "
领导者应该努力制裁不道德的行为，避免它恶化到引起监管者关注的地步。
eg. The federal government gambled hundreds of thousands of dollars in research funds to work on the project.
联邦政府为了这项研究计划冒险动用了好几十万美元的资金。
3. sum up
总结；概括；
eg. 'I love my wife, my horse and my dog,' he said, and that summed him up.
他说：“我爱我的妻子、我的马和我的狗。”他大致上就是这么一个人。
eg. Obree summed his weekend up in one word: 'Disastrous.'
奥布瑞用一个词总结了他的周末经历：“灾难。”
