Sam________some knowledge of the computer just by watching others working on it.

Though having lived abroad for years，many Chinese still________the traditional customs.

By far, there are many problems ________ to be solved.

He is amazingly cheerful considering all that he has      .

Do you know that a living cell can be       for a thousand years if the temperature is right?

This problem may lead to more serious ones if ____ unsolved.

     reasonable, the proposal he    attracted much attention．

After several rounds of I’m a Singer competition, Yu Quan _______ because of their excellent voices and performance.

As time went by, the plan stuck ________ fairly practical.

Many approaches have been _______ to control the spread of H7N9 Bird Flu.