— Was the problem solved at the meeting? — Not yet I’m afraid it may lead to more serious ones if _____ unsolved[ ]

(2013·江西南昌一模)It hasn’t been made clear ________ the new underground line is to be open to traffic

Fresh food is good for you . But you have to _______it first because sometimes it is a little dirty.

“We can’t go out in this weather, “said Bob, _____ out of the window.

It is ________ his tremendous enthusiasm and devotion that the old teacher is respected by all his students.