In today 's lesson you 'll learn how to express yourself when you don't know something in English.

This is actually such an easy method that I think by the end of this lesson, you 'll already start using it.

So let's have a look at the board and see how it works.

You start by using the phrase " I don't know " and you connect it to one of these words or expressions.

For example, " I don't know who is going to the party."

" I don't know what to do."

" I don't know what to say."

" I don't know what to cook."

Right? " I don't know when he 's arriving."

" I don't know where my glasses are."

" I don't know why she left her job."

" I don't know how to reach him."

" I don't know how to drive."

" I don't know how to swim." and so on.

" I don't know how much it costs."

" I don't know how many people were at the concert."

" I don't know how often he goes to the club."

" I don't know whether Jane has arrived."

" Whether " spelled like this w h e t h e r, means " if ".

All right, it's another word for " if ".

" I don't know whether Jane has arrived yet."

" I don't know if I locked the door."

" I don't know if I locked the door."

So, you can see that by using that one expression, " I don't know " with any of these words, you can express a range of information.

Now, a couple of points to keep in mind.

You can use this expression and combine it with present, past, or future tense.

What do I mean?

Well, you could say, " I don't know who usually goes to his parties." That's present tense.

" I don't know who went to his party." Past tense.

Or, " I don't know who is going to his party." Future tense. Right?

So you can do this with all of these words.

You can use it in the present, in the past, or in the future.

And one last very important point to keep in mind regarding the word " know ",

regarding the verb " know ".

The verb " know " is a stative verb. A stative verb means that you cannot use it in the continuous form.

You can only use it in the simple form, like this,

so you can only say " I don't know." not " I am not knowing."

Many people in different parts of the world use – - tend to use continuous forms for everything in English,

but you have to be really careful not to use the continuous forms with stative verbs.

" Know " is a very common stative verb. There are many others like it.

So, other than that, you're fine. You couldn't say...

Sorry, you could also say " I don't know " or " I didn't know ". All right?

So you can use this part but remember not to change the verb " know ".