This question examines the ability of students to use idioms. A, respected: high moral character and high prestige. Generally describe elders. B, concentration: refers to the concentration of research, to the point where others can't reach it. It also means taking pains to find a solution to the problem. D. make a mountain out of a molehill: it means to treat small things as big things, meaning that it is not worth doing or deliberately expanding the situation. None of these three items contains context.