单选题 ______ policy makers struggle to define and implement appropriate legislation, development of the most destructive kind has continued over vast areas.

A、 As long as
B、 As
C、 Even
D、 While

【正确答案】 D

【答案解析】as long as表示“如果，只要”，引导条件状语从句，as引导原因或方式状语从句。while可引导让步状语从句，表示“尽管，虽然”。even不是连词，不引导句子。根据句意，D正确。