1.... I had no idea how to do it. I tried to stay positive and persevered ____ I finally found the solution.
A.and B. until
2.With the problem ___ (solve)
A.solved B. is solved
3.When they need advice, they don't usually go to the people they know.____ many of them write letters to newspapers and magazines .
A. Instead B.but
4.I like the clothes there, ___ they look very beatiful
A. for B.because