在《动词与主语必须呼应——动词的运用有学问》一文里，谈到动词与主语呼应问题，并提出五个指导原则，以避免这方面的错误。但是指导归指导，错误还是像不速之客，如影随形，频频来访。在学生作业中，这种错误排列第一。其他场合也常见到动词与主语不搭配的语病。下面这广告第一句中的形容词分句里便出现了这种错误：
“Dear Owner/Resident, we have ready buyers who is upgrading.”
根据英语语法规律，形容词分句（也叫定语从句，adjective clause）里的动词必须和主句里的先行词（antecedent）呼应。先行词是单数，形容词分句中的动词便是单数；先行词是复数，形容词分句中的动词便是复数。例如：
① Do you know the woman who is walking the dog?（陪狗散步）
② Those who have performed well in the tournament will be rewarded.
在①里，先行词 the woman 是单数，形容词分句里的动词 is 也是单数。反之，②里的先行词 those 是复数，who 后面的动词也是复数 have.
根据这原则，who is upgrading 中的 is 便要改为 are 了。
动词与主语不呼应的错误比比皆是。除了上述例子外，常见的错误还有下面几种类型：
③ Has Mr and Mrs Li decided to emigrate?
④ Do your uncle live in Malaysia?
⑤ There is several beautiful paintings on the wall.
⑥ The news of Henry s resignation were received with great surprise.
⑦ What we are doing are good for the nation as a whole.
⑧ Someone have forgotten to turn off the light.
在③里，助动词 has 和复数主语 Mr and Mrs Li 不符，要改为 have.第④句里的 do 和 your uncle 不搭配，要改为 does.第⑤ 句里的 is 和真正主语 paintings 的数不一致，应改为 are.这个句子也可改变为：“Several beautiful paintings are on the wall”。在⑥里的主语 news，其形式是复数，但意思是单数，动词也要单数的 was received 才行。⑦里的主语是名词分句（noun clause），是个单数的单位，动词也要单数的 is，不是 are.在⑧ 里的主语 someone 是单数代名词，随后的动词必须是 has forgotten 才对。
上述动词和主语不一致的毛病，屡见不鲜；即使英语能力好的人，也难幸免。
下面这句英语很好，但是里面的动词对吗？是 has 还是 have 呢？
“Its unique concept and impressive magnitude has made it the talking point of the region.”
既然这句的主语是由 concept 和 magnitude 组成，便是复数，谓语动词当然也要复数 have 才是。