第18题: [单项选择]The school board listened quietly as John read the demands that his followers ______ for. A. was demonstrating B. demonstrate C. had been demonstrating D. have demonstrated 参考答案:C 答案解析:[解析] 根据题意,空档所在部分为定语从句,先行词为demands。根据一致原则,可将B和D先排除。as从句中,read这一动作明显先于demonstrate这一动作,因此C为正确答案。