其实不仅仅对实义动词作谓语,对能单独作谓语的任何动词(包括be动词,系动词)的主语提问时都不用加助动词。如:Li Hua is a student. 对Li Hua (主语)提问:Who is a student? 再如:Spring comes after winter. 对Spring ( 主语)提问:Which season comes after winter?