题目

若直线和圆相切与点，则的值为（    ） A．             B．             C．           D． 答案：C20、Mr. Smith left his car outside his house one night as usual．But when he came out the next morning，he found his car wasn’t there．He called the police to tell them about it，and they said they would try to find it．     When Mr. Smith came home from his office that evening，the car was back again in its usual place in front of his house．He looked it over carefully and found it OK．But there were two tickets on one of the seats with a letter．It said，“We’re sorry we used your car for a day．Thank you very much．The tickets are for you．We hope you’ll enjoy yourselves．”     The Smiths went to the cinema with the tickets at night．When they got home，they found nearly everything in the house was gone． 根据短文内容，判断正（T）、误（F）。 （   ）1．Mr. Smith came out the next morning but he couldn’t find his ear． （   ）2．Someone used his car for three days． （   ）3．The Smiths called the police but they would not like to help them． （   ）4．The two tickets on the seat showed real sorry to the Smiths． （   ）5．The thief gave Mr. Smith two tickets and took away almost everything．