—— Hurry up. The bus is coming! —— Oh, no, we mustn’t cross the street ______ the traffic lights are green.
Deng Yaping went to Tsinghua University and __________ English and management.
—_________ did your play soccer? —For three years.
I have a _________ sister. She is two years old.
She toured China __________she was fourteen.
Michael Jordan is an __________ basketball player.