重点讲解：
1. for free 义务地；无偿地；免费地；
The company won the contract by essentially saying it would do the job for free.
那家公司基本上是靠宣称免费进行那项工作才赢得了合同Hz;9v^]-*)Q0#_fjCx;。
2. laugh at 嘲笑；讥笑；
I thought they were laughing at me because I was ugly.
我觉得他们嘲笑我是因为我长得丑,|uEBd&th9iZHg(_2Z*。
3. hang up 挂断（电话）；突然挂断…的电话；
Mum hung up the phone.
妈妈挂上了电话PD,zwdS(LQ!JMb54o[x。
4. benefit from 获益；对…有益；有利于；
Both sides have benefited from the talks.
双方都从谈判中获益,QlG*az()nXF!W-。