It was __________ computer games that cost the young man a lot of precious time that heshould __________ on his lessons．

____ is known to all, China will be an _____ and powerful country in 20 or 30 years’ time. 

____the problem, it follows that we must develop a plan of action.

　　　late in the morning,Bob turned off the alarm.

While listening to the concert, the audience is required to remain ______ and keep quiet.