It takes time to build when you are learning a difficult skill.A. confidenceB. strength C

问题补充：

It takes time to build when you are learning a difficult skill.

A. confidence

B. strength

C. energy

D. belief

答案：

(答案→)A. confidence

B. strength

C. energy

D. belief

解析：考察名词词义辨析。A信心；B力气，优势；C能量，能源；D信念；句意：当在学习一个困难的技能的时候，建立信心要很长的时间。根据句意说明A正确。