. I’ve no idea. I just pretended nobody was at home, so I didn’t ask who _______ was.
__________him not to do so, he wouldn’t have made such a serious mistake.
Scientific researches show that to __________ a language one had better often get exposed to it.
To reduce emissions of greenhouse gases, many countries are increasing the use of natural gas, wind and other forms of _______ energy.
In most cases, college graduates don't mind what job they will do so long as it is one ______ they can earn money to support themselves.
__________ our efforts to save houses dating back to the Ming Dynasty, the local government decided to pull them down to build modern buildings there.