kkk0168

Jack like studying history very much. one sunday mornning, he was planning to visit a museum. he hurried to the station to catch the 7:30 train. as soon as he got there, he tried to buy a ticket for that train. the ticket clerk said  'the 7:30 train has just left,  the next train will leave in 30 minutes.""has the train gone already? it is 7:27 by my watch" said Jack. the clerk said with a smile"look at that clock on the wall, it is already passed 7:30, your watch is 3 minutes slow."