He began to take political science        only when he left school.

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

He thought this was the first pair of shoes that had fitted him _____.

—How is everything going on with you in Australia?—Quite well. Not so smoothly as I hoped, _______.

 There was a long queue for coffee. Having waited for 10 minutes, we ____ gave up.