单选题
A series of lectures on radio engineering ______ scheduled. A. have been B. has been C. are D. had been
【正确答案】
B
【答案解析】[解析] 以series of+名词(复数)作主语时，谓语的数与series保持一致。series单复数词形不变，以a series of作主语时，谓语动词用第三人称单数；以two series of作主语时，谓语动词用第三人称复数。用法与此相同的名词还有means，/species/sheep等。