—The research on rescuing as many coal miners as possible is challenging and demanding. Who do you think can do the job?—________my colleagues have a try?
I must go now. _____, if you want that book I'll bring it next time.
Achieving a high degree of proficiency in English as a foreign language is not a mysterious _____ without scientific basis.
They were so far away that I couldn't _____ their faces clearly.
If the boy had _____ the dog alone it wouldn't have bitten him.
The generation _____ makes it difficult for parents to understand their children's opinions.