26．_______ all the seats were full, he had no choice but to stand up.
A. For B. As
C. Though D. Unless
[解析]句意：因为所有的座位都满了，他除了站着别无选择。as 用法很多，用作连词，意为“当……时候”时，引导时间状语从句；“因为，既然”，引导原因状语从句；“如同”，引导方式状语从句；由语境可知，此处 as 引导原因状语从句。
[答案]B
27．I will never forget such a beautiful place ________ I spent my childhood there with my grandparents.
A. that B. where
C. because D. in which
[解析]句意：我将永远忘不了这么美丽的地方，因为我跟爷爷奶奶在那儿度过了我的童年。由句意可知，此处是 because 引导的原因状语从句。
[答案]C
