It has always been the _____ of our firm to encourage workers to take part in social activities.
The old professor, to_______ the important invention _______, decided not to keep it for himself, but to make it known to all over the world.
It remains ______ whether Liu Xiang will take part in the next Olympics.
I don’t think the problem you referred to is worth______.
---I’m taking part in the 200-meter race tomorrow. ---_________.
—Why didn’t you tell him about the exciting news? —He rushed out of the room ______ I could say a word.