Plans have been proposed ______ the largest dam in the world to be built along the Congo river.
If China’s space technology has achieved breakthrough in this field, it really is amazing wonder.
All passengers ____, please fasten your seat belts and remain seated ____the plane is landing.
He ____ busy then; otherwise, I believe, he would have given you a hand.
It is not like Mr.Smith, who is a gentleman, _____his wife so rudely.
As the saying _______, _______ who laughs last laughs best.