Plans have been proposed ______ the largest dam in the world to be built along the Congo river.
--- Hey, can I ask you a favour?--- Sure,______ (2013 .浙江)
Mother always complains that children ______ their shoes very quickly. (2013 .江西)
Before you pay a visit to a place of interest, look in your local library ______ a book about it. (2013安徽)
Traditionally, college students hold a graduation ceremony to encourage themselves before they ______ on their life journey.(2013 .安徽)
Walking alone in the dark, the boy whistled to ______ his courage.(2012 .湖北)