A modern university has been set up in ______ used to be.
Low-carbon lifestyle is of great benefit to improve the world environment, but the problem is difficult to _________.
After ten years abroad, he still recognized his old colleagues ________ he set foot in China.
We won’t forget the financial crisis and the troubles _______ has caused to the people all over the world.
Thanks for your kind help! We would have _________ lost the game!
— What’s that noise? Is the water still running? — Oh, my god! I ________to turn it off after I brushed my teeth.