题目

听下面一段较长对话，回答以下小题。【1】Where does the conversation probably take place?A.In a store. B.On a plane. C.At an airport.【2】How much will the man pay at last?A.$220. B.$476. C.$515. 答案：【答案】【1】C【2】B【解析】【原文】W: United Airlines. May I help you?M: Yes, I'd like to book a ticket for Flight 220 leaving for Honolulu on December 22nd at 7: 30 in the evening?W: Do you want to fly first or economy class?M: Economy please.W: Will this be a one-way trip?M: No, round trip back to Chicago By the way, do you have any direct flights coming back?W: Yes, we do. Flig10．常温下，20mLpH=1的硫酸溶液：（1）溶液中由水电离产生的c（H+）=1×10-13mol•L-1，c（SO42-）=0.05mol•L-1．（2）若取出2mL该溶液，稀释100倍后，溶液的pH=3，（3）若将该溶液与10mL0.1mol•L-1NaOH溶液混合，混合后溶液的pH=1.48．（设混合后总体积为30mL，lg3=0.48）