main verb
noun [ C ] uk/ˌmeɪn ˈvɜːb/ us/ˌmeɪn ˈvɝːb/
主要动词（句子中与助动词相比较有意义的动词）
in a clause, the verb that contains the meaning, compared with any auxiliary verbs that go with it
In "I should have been studying", "studying" is the main verb. 在 I should have been studying 这个句子中，studying 是主要动词。