表语是在be动词,连系动词之后的句子成分,用来说明主语的身份,特征或者属性等。例如Tom is a top student.It sounds OK.宾语是在及物动词,或者介词后面的句子成分,表明动作涉及的对象。例如We reached the hotel before it got dark.we arrived at the hotel before it got dark.They are like brothers.