情景对话（每题1分，共5分）请将正确答案序号填到题号前，有两项为多余选项。

小题1:—I am sorry, I couldn’t find the book you want to borrow.

—________

小题2: —How was your visit to Lake Tai？

—______

小题3:—Professor Wang, I haven’t finished my paper.

—_____. You have some time left.

小题4:- The car looks nice. Could I have a try before I decide to buy it?

　- _____________

小题5:—Would you like another piece of cake?

—___________. I’m still hungry.

提高旅游企业经济效益的途径包括（）。

A.增加经营收入

B.节约成本总额

C.降低边际成本和收入

D.增收和节支

E.利用外部经济