Li Keqiang, graduated from __________ Department of Economics of Peking University,was elected _________ Premier of the People's Republic of China.
She turned ______ the pages quickly _____ a practiced hand.
The roads are lined _____trees, which have been planted to hold _____the strong winds from the north.
He earned enough money to start his own business _____ offering guide services _____ tourists.
_____ the night, we did nothing but _____ there, waiting for him to come.
_____ your help, we _____ complete the work in time.