Modal verbs, which express a likelihood, ability, permission, request, order etc., usually help main verbs to state the future. It is the reason they are categorised as auxiliary verbs in the context.

Here s a set of basic but tough grammar questions posted in Jose Carillo s English Forum by an Iran-based member who goes by the cryptic username r_a: What are the differences between a helping verb, ...

Many years ago, I was surprised but delighted to receive an email from a columnist of a Manila-based daily asking these two perplexing grammar questions: ...