第3题: [单项选择]The house was very quiet, ______ as it was on the side of a mountain. A. isolated B. isolating C. being isolated D. having been isolated 参考答案:A 答案解析:[解析] 结构识别 逗号后面的部分是原因状语从句as it was isolated on the side of a mountain,本句为了强调“被隔绝”之意,将isolated提