The traffic problems have severely affected economic development. ________, we must spare no efforts to solve them.

Some people are bad at recalling names and faces, so it's possible that they have a condition called face blindness, ______ people suddenly have trouble recognizing family members, friends or even themselves．

Wang Ping hesitated for ___ before he ___ to the question.

 I’d like to start my own business next year – that’s _________ I will face my big challenge in life.

He trained hard in puzzle-guessing, a sort of children’s game, all year, _____ still failed to reach his best form in all the tests given to both adults and children.