.Every year in April, the Water Festival ______ among the Dai people in Xishuangbanna.

.Lewis searched for his ID card for a whole day last Sunday, but it ____ in his pocket the next day.

They use computers to keep the traffic _______ smoothly. 

 Richard was called in by the police to answer questions _______ the disappearance of Thomas Ripley, whose relatives were so ______ his present situation.

Sarah hopes to become a friend of _____________ shares her interests.