Every sentence that you read will have a verb to describe an action (action verbs) or condition (linking verb) describe within it. These actions or conditions can take place once or over time. Writers will also include a secondary verb in some situations to add a nuance to a sentence. The secondary verb can be used to express a tense, give a voice, form a negative or a question. These secondary verbs are called helping or auxiliary verbs. The most common forms of these verbs are be, do, have, and is. These words often attach themselves to the main verb within the sentence. They are also the most common verb form found in the English language. One simple way to identify these verbs is to look for verbs that express a tense, that is a dead giveaway.
A distinction of a modal auxiliary verb is that they never change form which means that they will not -ed, -ing, or -s endings. This is because they only have one form. This would include words such as: can, could, shall, should, will, and would. Modal auxiliaries express a sense of obligation, indicating that something must be done. These worksheets will help students learn to identify and properly use these verb forms in sentences.