Understanding Modal Verbs in English Grammar

Modal verbs are a type of auxiliary verb used to express possibility, necessity, probability, permission, obligation, ability, and advisability. They do not indicate grammatical tense like regular verbs; instead, they convey moods such as potentiality, permissibility, or necessity. In English, modal verbs usually occur with base forms of other verbs and take the infinitive form of these other verbs without '-to'. Here is a breakdown of some common modals and their uses:

Could

This modal indicates either possibility or ability:

• I could help you if needed. (Possibility)
• She couldn't finish her work because she was sick. (Inability)

May

May implies both possibility and permission:

• May I speak now? (Permission)
• It may rain today. (Possibility)

Might

Might suggests something more probable than 'may', indicating likelihood or probability:

• He might have gone out of town this weekend. (Probably went away.)
• This situation might worsen soon. (Likely to deteriorate.)

Must

Must conveys obligation, necessity, or conditionality:

• We must leave now to catch our flight. (Necessary to leave.)
• You must wear your seatbelt while driving. (Obligatory safety measure.)

Can

Can signifies capability or power, often used to ask for abilities:

• Do you know how to swim? (Asking about swimming proficiency.)
• Can I bring my pet here? (Seeking approval to bring a pet.)

These modal verbs can appear in different structures within sentences. Generally, when one word functions as both a preposition and a conjunction, it does so only after a certain kind of verb—one that typically comes first in its clause. If the verb is an action verb, we use the prepositional phrase before the main verb, as in "She helped him." However, if the verb is a state verb like 'be', we place the prepositional phrase after the main verb, as seen in "He was in his office working." These complexities make mastery of modal usage crucial for effective communication.