The classroom is so dirty. _________ we clean it?
It is by no means clear ________ the president can do something to end the strike.
Good shoes, clothes and a backpack are the basic ________ you need for your hiking.
The Australian boy has a good ________ of Chinese and can express himself freely in it.
—How can I use the equipment?—Well, just refer to the ________.
—Do you know why Jane was so angry?—Her roommate gave in to ________ and opened the letter addressed to her.