15.听下面一段材料,回答第15至第17题. 15.What is Jack going to do this summer holiday? A.Stay with his own family B.Stay with an American family C.Stay with his classmates 16.How is Jack going to LA? A.By ship. B.By train. C.By plane. 17.When is Jack leaving for New York? A.On 1st June. B.On the end of the journey. C.On 1st July.