He has by chance _____ the answer to that problem.
The old man said the accident________ careless driving
I don’t think _________ is possible to master a foreign language without much memory work.
—Thank you very much for everything .You’ve been so helpful .—_ _.Just let me know if there is anything else I can do for you.
Please remind your grandpa to take medicine on time, for a man of his age ____be very forgetful.
During the economic crisis, we should help those for ______life is far from easy.