efficient
/ɪˈfɪʃənt/adjective
1- (especially of a system or machine) achieving maximum productivity with minimum wasted effort or expense（尤指系统或机器）效率高的：
fluorescent lamps are efficient at converting electricity into light.
荧光灯能将电能高效地转换成光能。
1.1
- (of a person) working in a well-organized and competent way（人）有能力的, 能胜任的：
an efficient administrator.
一位有能力的管理者。
1.2
- in combination preventing the wasteful use of a particular resource防止造成…的浪费的：
an energy-efficient heating system.
一种节能的供暖系统。
派生词
efficiently
adverb词源
late Middle English （in the sense 'making, causing', usually in EFFICIENT CAUSE）： from Latin efficient- 'accomplishing', from the verb efficere （see EFFECT）. The current sense dates from the late 18th cent.