1.It was only when they had eaten all the food that they finally from the table.
A.got up B.left behind C.went away D.stood on
A is correct. Even thought your answer C makes grammatical sense, the traditional phraseology is "to get up from" the table once one is finished eating. (Most likely because you have to rise from a sitting position before you can leave.)
2.In the past decades, the farms of the world have__________succeeded in producing enough food to feed all of the planet's people.
A.relrvantly B.externally C.utterly D.virtually
It would ultimately depend upon the context, but I'd say that D is correct. A and B don't make any sense in this context. "Utterly" means absolutely or entirely; "virtually" means almost, but not quite; or practically.
3.I'm __________enough to know it is going to be a very difficult situation to compete against three strong teams.
A.relistic B.conscious C.aware D.radical
I'm going to disagree with both your answer and the Suggested Key. Again, the correct answer would ultimately depend upon the context, but as shown, my answer would be A. I'm realistic enough, meaning I'm not giving myself false hope - I understand that I'm facing a difficult situation and I'm prepared.
4.Before he started work , I asked the builder to give me an _________of the cost of repairing the roof
A.assessment B.announcement C.estimate D.evaluation
Although A makes grammatical sense, in this case C is the correct answer. When you're dealing with contractors, builders and construction workers, you always ask them to look at the necessary repairs and then give you an estimate of the costs. It's a word that's specific to that industry.