udy in Peking University lasted four years, ______ he founded his own company in Hong Kong.

It was the hurricane ______ was called Katrina ______ destroyed the city of New Orleans.

(2013·合肥一中二模)The school recommends parents ________ their children to swim in rivers or lakes during summer holidays.

fill up fast during the busy tourist season, __________it is necessary for tourists to make reservations in advance.

下列各组加横线词的意义完全相同的一项是（ ）