In Cos Angel, a waiter served a group of teens. The waiter remembered his experience as a young high school prudent. So he made sure the teens had a pleasant experience at the restaurant. The waiter made sure of it. After serving all the teens doing a great job, he was left a tip( 消费 ),only$3.28. That was hardly enough to buy a drink at Roebucks. The waiter went home. And he felt hatred for the students who did not know the value of hard work. They looked down on people like him. Or so he thought. After several days, the waiter forgot about it. His life went on as usual. But ten days later, he received a letter from the teens. “About a week and a half ago, on October 7, my three friends and I came to eat at this restaurant as our own homecoming celebration. It was an exciting experience for us to be here alone, and it was all new to us. And you were the best waiter we could ask for. You were kind, helpful, and didn’t treat us like babies! So I want to say thank you for making our ‘groan-up’ experience so amazing and fun. “I would also like to say sorry on behalf of( 代表 ) my group. Since we were new to all of this, reasonable( 合乎情理 ),but we had completely forgotten(and didn’t know,to be honest) what a tip even was, let alone how much to give. So we emptied our pockets, and all our money added up to $3.28. “Having no idea of how small this really was ,we left. Later, we realized our mistake and felt terrible. We knew we had to make it right. “So together with this letter, you wail find the correct 18% tip + extra for simply being amazing. Thank you for your help and patience and also thank you for making our night fun. Thank you!” 2.Why did the group of teens leave that small tip? A.Because they looked down on the waiter. B.Because they didn't know what a tip meant. C.Because they weren't pleased with the service. D.Because they thought the tip should be that much. 3.What made the teens write the letter? A.The tip they left for the waiter. B.The bill the restaurant received. C.The way the waiter served them. D.The fun they had at the restaurant. 4.What do restaurant waiters mind most in America? A.What kind of guests they receive. B.What dishes people usually order. C.Whether they are given reasonable tips. D.How much customers pay for their meals.