from the top of the tower ,the south foot of the mountain is a sea of trees.

  I stood there patiently until he ________ his work.

Every possible means ________, but the teacher as well as the students ________ found a solution to the problem yet. 

— Are you a member of the club?—       . It’s years since I       .

—How long do you think it is ________ he arrived here?　　　　—No more than half a year, I believe.