Science and technology is changing fast nowadays. I bought this MP3 player at the beginning of this year but now it's out of________.
The _______, I think, he drew from his simple experiment is not scientific.
Alice received an invitation from her boss, ________ came as a surprise.
Most people find it hard to ________Beijing Opera to foreigners because of cultural differences.
At the age of fifteen she gave up taking piano lessons to _____ her school work.
It is still under discussion _________ the old bus station should be replaced with a modern hotel or not.