Many explanations have been proposed for why dinosaurs became extinct. For exa
mple, some have blamed dinosaur extinction on the development of flowering pla
nts, which were supposedly more difficult to digest and could have cost consti
pation or indigestion

我个人看法是--题目是问flowering plant evolved，文章中出现在except后，代表跟前面论点相反，讲的是恐龙能够消化这些flowering plant了，所以是对前面解释恐龙绝种的论点提出疑问

恩 感谢解惑

态度解题，(A) 是一面倒，(B) 是两边拔河，文章有前后对比及疑惑，选 (B)