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