イギリス英会話ブログ

Junior High School students usually start their English studies by learning the verb ‘to be’, then they study the 一般動詞. There is another group of verbs called ‘modal verbs’, which have a slightly different grammar. ‘Must’ is one of these verbs.

Have a look at this example conversation :

A : We’ve just got back. It took five hours and I drove all the way.

B : You must be tired.

Here you can see that MUST is followed by an infinitive. The meaning of this last sentence is 「疲れたに違いないね」 or 「疲れたでしょう」.

Can you think of a similar response to these statements?

1. “I failed the Japanese test.” -
2. “I haven’t eaten anything today.” -
3. “Look at that guy! He can hardly walk straight.” -
4. “My cat died yesterday.” -

Of course, you can sometimes use other verbs apart from ‘BE’ :

A : The 3 of us drank a case of beer last night.

B : You must have a hangover.

A : Yes, I do feel a bit rough.

Try translating these sentences :

1. 彼女は、そとで待っているに違いない。
2. 彼は、アメリカ人に違いない。
3. あなたは、儲かっているに違いない！
4. 彼はもう知っているに違いない。

MUST is used like this when we draw logical conclusions based on evidence that we can see or hear or feel, etc.. We mean that ‘I am sure this is true based on the evidence available to me’.

A : Look at all these trophies!

B : Yes, he must be a karate champion or something like that.

Verbs like MUST do not have a past tense form. Because of this, to express an opinion about some past happening or event we have to use the ‘Present Perfect Infinitive’. Like this :

A : We’ve been waiting nearly an hour.

B : Yes, and he’s not answering his phone.

A : He must have forgotten about meeting up with us.

B : Yes, or something must have happened to prevent him coming.

Try translating these past tense sentences :

1. （私は）間違えたに違いない。
2. 彼女は、英語がとても上手で、アメリカやイギリスなどに住んだ事があるに違いない。
3. 彼らは、道に迷ったに違いない。
4. （あなたは）もうグレッグさんに会ったことがあるでしょう。

Another similar verb is CAN’T, and I’ll be looking at that in the next post.