Detective stories（53） （be）popular since Conan Doyle wrote his famous stories about great detective Sherlock Holmes．Readers read this kind of stories mainly for pleasure．
In a story，a man was murdered．Who did it and why？Mr. X hated the dead person and wanted to kill him，but had no chance．He was somewhere else when the murder took place．Mr. Y could do it easily，but seemed（54） （have）no reason to do it．Mr. Z had got all the dead man's money，so he had reason for（55） （kill）him．Was X，Y，or Z the murder？Or was it somebody else？In the end the detective will find out the answers to all the questions，and the story will not end until the mystery（56） （solve）．
The ending is always unexpected．The criminal turns not to be that nice Mr. C，who you（57）______（think）would never hurt an ant! At end of the story，all the clues become clear and you（58） （say），"Oh yes，of course，it is the truth．"
Is there any （possible）that we will see you this Friday．
Once a week my business suit is （smooth） ironed．
My grandfather showed an interest in Beijing opera in his （fifty ）．
How shall we travel？By train or by plane？
Let's go by train，It's （cheap）．