To his mind, the collaborative development of Beijing, Tianjin and Hebei province is to solve the problems _____ Beijing faces, such as overpopulation, traffic jams, and etc.
Willpower is a kind of quality, _____ is _____ it takes to do anything well.
I was so familiar with him that I recognized his voice _____ I picked up the phone.
It’s reported that the police will soon ____ the case of two missing children.
Tom is keen _____ surfing the Internet in his spare time.
The students were completely _____ in their reading.