Write out three columns -- past, present, future -- on a transparency, blackboard or large piece of paper. Leaving sufficient space beneath these titles, list a number of events. Include items such as your birth, the election of Barack Obama, baseball season, the first voyage to another star system, summer and other events from past, present and future.
Ask students to place events in the proper column and write sample sentences about them. Inevitably, they will use a variety of verbs and verb tenses as they write. When they are finished, point out the tenses they used and the way they formed them. If some of the sentences use more complicated tenses, such as the perfect or progressive tenses, ignore them and focus on those that use simple past, present and future.
Continue by explaining that the simple present tense is one of the most common tenses in English. As an example, use one of the verbs expressed in the simple present in the student sentences or write a new sentence inspired by one of the examples and use the main verb from that sentence. Write out all the personal pronouns and show how the verb stays the same in all but one of those cases. Verbs used with third-person singular pronouns add -s at the end. Allow students to suggest other verbs and put them through the same transformation.
Take one of the regular verbs from the past tense column. This should be a verb that will only add --ed at the end. Put this verb through the same routine used for the simple present. Then tell the children about irregular past tense verbs that do not add -ed at the end. They probably already know many such examples, such as 'eat' becoming 'ate.' Write the simple present of these verbs on strips of paper and put their past tense version on different-colored strips. Let the children match the verbs in their present tense form with their past tense.
Point out examples of simple future tense verbs that the students used. Explain that this tense is the easiest to form because there are no irregular situations. Just add 'will' before each verb and use with any subject.