2. obsess   verb   

原句: Group-buying websites—Groupon, LivingSocial and dozens of smaller ones—are the latest craze among price-odsessed consumers and an evolution of social media and shopping.

意思:
a. to completely fill your mind so that you cannot think of anything else, in a way that is not normal
b. to be always talking or worrying about a particular thing, especially when this annoys other people

字源: late Middle English (in the sense ‘haunt, possess’, referring to an evil spirit): from Latin obsess- ‘besieged’, from the verb obsidere, from ob- ‘opposite’ + sedere ‘sit’. The current sense dates from the late 19th cent. 

例句:
a. She's completely obsessed with him.
b. I think you should try to stop obsessing about food.



3. overwhelming   adjective   

原句: I'm not prepared to say it's an overwhelming long-term consumer trend.

意思: very great or very strong; so powerful that you cannot resist it or decide how to react 

例句: The evidence against him was overwhelming.



4. effusive   adjective   

原句: Gregg Pupecki, sales and marketing director for Wendella Boats & Chicago Water Taxi, is more effusive.

意思: showing much or too much emotion 

例句: He was effusive in his praise.



5. discount   noun [countable/uncountable]   

原句: His company sold more than 5,000 discount tikets on its first Groupon promotion and 20,000 on the next.

意思: an amount of money that is taken off the usual cost of sth

字源: early 17th cent.: from obsolete French descompte (noun), descompter (verb), or (in commercial contexts) from Italian (di)scontare, both from medieval Latin discomputare, from Latin dis- (expressing reversal) + computare, from com- ‘together’ + putare ‘to settle (an account)’. 

例句: They were selling everything at a discount.