English Using Passive Voice with Modals, Definition and Examples In construction of appropriate sentences, many times we’re wrong because we can not find the right word. This is where modals come in. We use verbs according to the requirements of the actions that we want to describe. The main verb describes the action but modals are helping verbs, helping to improve the sentence by communicating much more than the main verb alone. Modal verbs normally precede the main verb and provide additional information about the function of the main verb. The modals cannot be used alone and they always appear