Explanations:In English grammar, modal verbs are auxiliary verbs that are used to express various degrees of possibility, probability, ability, permission, and obligation. Common modal verbs include "can," "could," "may," "might," "must," "shall," "should," "will," and "would." One of the key features of modal verbs is that they are always followed by the base form of the main verb, also known as the infinitive form without "to."
For example, in the sentence "My cousin, Lily cannot swim well," the modal verb "cannot" is followed by the base form of the verb "swim." The base form of the verb is the simplest form of the verb, which is used after modal verbs and in the infinitive form. It is important to note that the base form of the verb does not change for different subjects or tenses when it follows a modal verb.
Let's break down the sentence "My cousin, Lily cannot swim well" to understand the structure better:
1. "My cousin, Lily" is the subject of the sentence.
2. "cannot" is the modal verb, which expresses the ability or inability to do something.
3. "swim" is the base form of the verb that follows the modal verb "cannot."
4. "well" is an adverb that modifies the verb "swim" and describes how the action is performed.
It is crucial to remember that the base form of the verb is used after modal verbs, regardless of the tense or the subject of the sentence. For example:
- "I can swim well."
- "She can swim well."
- "They can swim well."
In all these sentences, the base form "swim" is used after the modal verb "can." This rule applies to all modal verbs, including "could," "may," "might," "must," "shall," "should," "will," and "would."
Incorrect forms such as "swims," "swam," or "swum" would not be used after modal verbs. For instance:
- "My cousin, Lily cannot swims well." (Incorrect)
- "My cousin, Lily cannot swam well." (Incorrect)
- "My cousin, Lily cannot swum well." (Incorrect)
These forms are incorrect because they do not follow the rule of using the base form of the verb after modal verbs. The correct form is "My cousin, Lily cannot swim well."
Understanding the use of the base form of the verb after modal verbs is essential for constructing grammatically correct sentences in English. It is a fundamental concept in English grammar and is frequently tested in various language proficiency exams such as TOEFL, IELTS, SAT, and ACT.