There are three primary auxiliaries: “be”, “do”, and “（）”.

猜你喜欢

• Semi-auxiliaries constitute a category of verbs between auxiliaries proper and main verbs.
• The past tense forms of auxiliaries do not necessarily express past time.
• Auxiliaries fall into three categories: （） auxiliaries, modal auxiliaries and semi-auxiliaries.
• A （） verb phrase is a main verb preceded by an auxiliary or auxiliaries and it may also contain modifiers.