【English Communication I】 Let’s Master Modal Verbs!
Hello everyone! Today, let’s study modal verbs, the magical words that add "nuance" (feelings or specific situations) to your English sentences.
The role of a modal verb is to add "flavor" to a verb, like adding spices to a dish—turning "do" into "can do," "might do," or "must do." Once you learn how to use these, you'll be able to express your thoughts much more accurately!
It might feel a little tricky at first, but the rules are very simple. Let’s learn together and have some fun!
1. The "Absolute Rules" of Modal Verbs
There are only two important rules you need to follow when using modal verbs.
Rule ①: Always use the "base form" of the verb afterwards
The verb that follows a modal (can, must, should, etc.) must always be in its base form (the form exactly as you see it in the dictionary). Do not add -s or change it into the past tense.
× He can plays soccer.
○ He can play soccer.
Rule ②: Never add -s to the modal verb
Even if the subject is He or She, you never add -s to the modal verb itself.
× She musts go.
○ She must go.
【Pro-tip!】
Think of modal verbs as always standing "before" the main verb to support it!
2. Common Modal Verbs and Their Images
Let’s grasp the "character" (the mental image) behind each modal verb.
① can (can do, may do)
Image: 100% full battery of capability/possibility
Its basic meaning is "having the power to do something."
Ex: I can swim.
It is also used to give permission, meaning "you are allowed to."
Ex: You can use my pen.
② may (might, may do)
Image: A fluttering "leaf"
It expresses a vague, 50% guess: "it might happen."
Ex: It may rain tomorrow.
It is also used for permission, but more politely than can.
Ex: May I come in?
③ must (must do, must be)
Image: An inescapable "wall/pressure"
It expresses strong obligation ("You absolutely must!") or strong certainty ("It must be true!").
Ex: You must do your homework.
Ex: He must be tired.
④ should (should do)
Image: An "arrow" pointing the way/advice
It carries the image of friendly advice, like saying "it would be good for you to do this."
Ex: You should sleep early.
⑤ will (will do)
Image: A "strong determination" heading toward the future
It expresses a decision to act or a prediction about the future.
Ex: I will help you.
【Did you know?】
Using Can I...? with friends and May I...? with teachers or superiors will make your English sound very natural!
3. Common Mistakes: The Difference in Meaning with Negatives
Be careful—when you add not to a modal verb, the meaning can change drastically. This is a favorite point for tests!
● must not vs. don't have to
This is a common point of confusion! Let’s distinguish them clearly.
must not = "must not do" (strict prohibition)
don't have to = "don't need to do" (lack of necessity)
Ex:
You must not run here. (You are forbidden to run! ← Against the rules)
You don't have to run. (You don't need to run. ← You don't have to hurry, it's okay.)
【Memory Trick】
Try to imagine the situation: Is it a "prohibition" or is it "your choice (you don't have to)"?
4. Comparing the "Strength" of Advice
When suggesting something to others, the intensity of your expression changes.
- had better + base form (You'd better do it! Or something bad will happen!) *Very strong, close to a warning.
- should (You should do it. It’s recommended.) *General advice.
Using had better casually with friends might make them think, "Why are you so angry?" So, it is safer to stick with should.
5. Summary: Key Points for Today
Finally, let’s review the important things we learned today.
・Always use the "base form" of the verb after a modal!
・must not means "prohibition," while don't have to means "it's not necessary (you're okay not doing it)"!
・Remember modal verbs by their specific "images"!
Modal verbs might look overwhelming because they have many meanings, but you will get the hang of them by reading example sentences aloud repeatedly. Start by using familiar ones like can and will. I’m rooting for you!