[al:新概念英语(第1册)第115课(听力强化·美)] [ti:Knock, Knock!-敲敲门! [ar:© 2011 露珠英语工作室] [by:http://weibo.com/DewEnglishStudio] [00:00.00]Carol and Tom invited us to lunch.-卡罗尔和汤姆请我们来吃午饭。