We went through a period _______ communications were very difficult in the rural areas. A, which B, whose C, in which D, with which
His younger sister may already be in high school now, in ________ case this picture book is too childish for her.
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 ________.