表达指令、要求、建议等意思的句子里宾语从句的谓语通常用动词原形,无论其主语是单数还是复数.这一点在美语中尤其讲究.在英式英语中或许 should + 动词原形和现在时都不算错.
上面的句子在美语中被认为是不正确的.即便主句谓语是过去时,从句谓语也是动词原形：
They demanded that the manager give them an answer.
类似的动词还有：
They suggest that the manager give them an answer.
They request that the manager give them an answer.
They ordered that the manager give them an answer.
.