1. Biologist agree that snakes descended from lizards, but exactly where this first happened has been a matter of debate since the 1800s, when two _______ theories emerged.
A complex
B competing
C dubious
D conclusive
E contending
F irrefutable
解析:
when在此處為關係副詞,指前方1800s,此題僅需掌握關鍵字debate及句尾emerge,即可找出答案為B competing與E contending。
* descend from 起源於
* lizard 蜥蜴
* debate 爭論
* emerge 出現
* complex 複雜的
* dubious 懷疑的
* contending 競爭的
* irrefutable 無可辯駁的=irrefragable=incontestable
2. Although Mount Saint Helens has been more (i)during the last 4,500 years than any other volcano in the conterminous United States its long dormancy before its recent eruption (ii)its violent nature.