题干
— I will go to Qingdao for my holiday.
— _____!
A：Good luck
B：Go ahead
C：I'm happy to hear that
D：Have a good trip
答案(点此获取答案解析）
D
— I will go to Qingdao for my holiday.
— _____!
A：Good luck
B：Go ahead
C：I'm happy to hear that
D：Have a good trip
、
两种单色光组成的光束从介质进入空气时，其折射光束如图所示。用