助動詞【must / should / can / may / cannotなど】を例文で英文法解説【練習問題あり】

I (    ) you flowers when I was your man.

I eat tomatoes.　「私はトマトを食べる。」

• I can eat tomatoes.　「私はトマトを食べられる」
• I should eat tomatoes.　「私はトマトを食べるべき。」
• I may eat tomatoes.　「私はトマトを食べるかもしれない。」

I can eat a green pepper.
「私はピーマンを食べられる。」
I should eat a green pepper.
「私はピーマンを食べるべき。」
I may eat a green pepper.
「私はピーマンを食べるかもしれない。」

I might see him yesterday.

• should have p.p
  「〜するべきだった。」
  
• may(might) have p.p
  「〜したかもしれない。」
  
• must have p.p
  「〜したにちがいない。」
  
• can't have p.p（can haveもありますが、使用頻度は低い）
  「〜のはずがない。」

I should have bought you flowers.
「私はあなたに花を買ってあげるべきでした。」

I may have met her before.
「以前、私は彼女に会ったかもしれません。」

She must have been at the library.
「彼女は図書館にいたに違いありません。」

He can't have got through such a small hole.
「彼がそんな小さな穴を通り抜けたはずがありません。」

The story can’t be true.
「その話は本当のはずがない。」
The story must be true.
「その話は本当に違いない。」

He can’t be hungry.
「彼は空腹のはずがない。」
He must be hungry.
「彼は空腹に違いない。」

The answer can’t be right.
「その答えは正しいはずがない。」
The answer must be right.
「その答えは正しいに違いない。」

You will can swim soon.

You will be able to swim soon.
「あなたはすぐ泳げるようになるよ。」

You wii must hurry to the station.

You wii have to hurry to the station.
「あなたは駅まで急がなくてはいけないでしょう。」

1. I (   ) you before, but I’m not sure.
   （1）might see
   （2）ought see
   （3）might have seen
   （4）may see
2. If it’s sunny tomorrow, we (   ) go to the beach.
   （1）would
   （2）can
   （3）want
   （4）have a plan
3. Having an unbalanced diet (   ) cause health problems.
   （1）is a
   （2）becomes
   （3）can
   （4）will be
4. He (   ) be over fifty; he must still be in his forties.
   （1）cannot
   （2）ought not to
   （3）shall not
   （4）need not
5. (   ) it be true that he bought a sports car?
   （1）Can
   （2）Do
   （3）Shall
   （4）Will
6. I really (   ) that radio next time I’m in New York.
   （1）should have bought
   （2）must buy
   （3）forget to buy
   （4）have bought
7. They are coming in the door with wet umbrellas. It (   ).
   （1）can’t rain
   （2）must rain
   （3）must be raining
   （4）can't be raining
8. You (   ) light a match. The room is full of gas.
   （1）have to
   （2）need not
   （3）must not
   （4）don't have to
9. Jim (   ) here by now. What’s happened to him?
   （1）should be
   （2）should have to be
   （3）must be arriving
   （4）cannot have arrived
10. Ken (   ) committed such a serious crime.
    （1）can be

    （2）cannot have
    （3）is
    （4）shall be

11. Something (   ) to my right leg when playing soccer yesterday. I can’t walk well.
    （1）must have happened
    （2）would have happened 
    （3）should have happened
    （4）won’t have arrived

12. Dick (   ) be here already. I’m afraid he has lost his way.
    （1）could
    （2）might
    （3）must
    （4）should

13. This morning I felt a serious pain in my back. I (   ) not have carried that heavy language upstairs.
    （1）must
    （2）should
    （3）may
    （4）can
14. I wonder where I lost my umbrella. I (   ) more careful.
    （1）should have been
    （2）need to have been
    （3）must have been
    （4）may have been
15. The boy solved the problem faster than anybody else. He (   ) be very intelligent.
    （1）has to
    （2）need not
    （3）must
    （4）cannot
16. I (   ) the movie, but I don’t remember whether I have.
    （1）should not have seen
    （2）ought to have seen
    （3）may have seen
    （4）cannot have seen
17. Tom (   ) there yesterday, but we didn’t see him.
    （1）should be
    （2）might have been
    （3）may be
    （4）must be

18. The boys should not (   ) the ice cream, but they did.
    （1）ate
    （2）be eaten
    （3）be eating
    （4）have eaten
    
    

1. I (   ) you before, but I’m not sure.
   （1）might see
   （2）ought see
   （3）might have seen
   （4）may see
2. If it’s sunny tomorrow, we (   ) go to the beach.
   （1）would
   （2）can
   （3）want
   （4）have a plan
3. Having an unbalanced diet (   ) cause health problems.
   （1）is a
   （2）becomes
   （3）can
   （4）will be
4. He (   ) be over fifty; he must still be in his forties.
   （1）cannot
   （2）ought not to
   （3）shall not
   （4）need not
5. (   ) it be true that he bought a sports car?
   （1）Can
   （2）Do
   （3）Shall
   （4）Will
6. I really (   ) that radio next time I’m in New York.
   （1）should have bought
   （2）must buy
   （3）forget to buy
   （4）have bought
7. They are coming in the door with wet umbrellas. It (   ).
   （1）can’t rain
   （2）must rain
   （3）must be raining
   （4）can't be raining
8. You (   ) light a match. The room is full of gas.
   （1）have to
   （2）need not
   （3）must not
   （4）don't have to
9. Jim (   ) here by now. What’s happened to him?
   （1）should be
   （2）should have to be
   （3）must be arriving
   （4）cannot have arrived
10. Ken (   ) committed such a serious crime.
    （1）can be

    （2）cannot have
    （3）is
    （4）shall be

11. Something (   ) to my right leg when playing soccer yesterday. I can’t walk well.
    （1）must have happened
    （2）would have happened 
    （3）should have happened
    （4）won’t have arrived

12. Dick (   ) be here already. I’m afraid he has lost his way.
    （1）could
    （2）might
    （3）must
    （4）should

13. This morning I felt a serious pain in my back. I (   ) not have carried that heavy language upstairs.
    （1）must
    （2）should
    （3）may
    （4）can
14. I wonder where I lost my umbrella. I (   ) more careful.
    （1）should have been
    （2）need to have been
    （3）must have been
    （4）may have been
15. The boy solved the problem faster than anybody else. He (   ) be very intelligent.
    （1）has to
    （2）need not
    （3）must
    （4）cannot
16. I (   ) the movie, but I don’t remember whether I have.
    （1）should not have seen
    （2）ought to have seen
    （3）may have seen
    （4）cannot have seen
17. Tom (   ) there yesterday, but we didn’t see him.
    （1）should be
    （2）might have been
    （3）may be
    （4）must be

18. The boys should not (   ) the ice cream, but they did.
    （1）ate
    （2）be eaten
    （3）be eating
    （4）have eaten