第21题: [单项选择]Although punctual himself, Dr. Smith was quite used ______ late for the appointments. A. for patients’ to be B. for patients’ being C. to have patients’ D. to patients’ being 参考答案:D 答案解析:[解析] be used to习惯于,后面跟名词或动名词,patients’being late为动名词短语。