单选题 His ______ behavior made everyone nervous. He was always rushing to open doors and perform other small tasks, apologizing unnecessarily for any inconvenience that he might have caused.
A．oblivious B．observant C．obsequious D．obsolescent

【正确答案】 C
【答案解析】[解析] 形近识别
A．oblivious遗忘的，健忘的；B．observant深切注意的；C．obsequious谄媚的，奉承的，逢迎的，卑躬的；D．obsolescent荒废的；因此C为答案。