UNIT 4
1. His employers could not complain about his work because he was ______ in the performance of his duties.
A. derelict B. penetrating C. diversified D. assiduous.

employer 雇主，老板
employee 雇员

assiduous 勤奋的
insidious 阴险的，狡诈的

derelict 遗弃物
relics 遗骨
relict 残余物

penetrate 穿透
permeate 渗透
diffuse 弥漫
diversify 使不同