John's working in a bar until he finds a job in his field.

[=Alex=]

Hello everyone! I do not understand when I should use Present Continuous (PC), and when Present Perfect Continuous (PPC) for temporary or new situations or habits. I don't see the difference between these cases.
Why can not I say these sentences in another tense?

• John's working in a bar until he finds a job in his field. (PC) -> John has been working in a bar until he finds a job in his field. (PPC)
• They've been living with his mother while they look for a house. (PPC) ->They are living with his mother wile they look for a house. (PC)
• I usually go to the gym on the High Street, but it's closed for repairs at the moment so I've been going to the one in the shopping centre. (PPC) -> I usually go to the gym on the High Street, but it's closed for repairs at the moment so I am going to the one in the shopping centre. (PC)

Both definitions are taken from here.
We can also use this tense for other kinds of temporary situations, even if the action isn't happening at this moment.

• John's working in a bar until he finds a job in his field. (He might not be working now.)
• I'm reading a really great book.
• She's staying with her friend for a week.

And here is another one.
We can use the present continuous for temporary or new habits (for normal habits that continue for a long time, we use the present simple). We often use this with expressions like 'these days' or 'at the moment'.

• He's eating a lot these days.
• She's swimming every morning (she didn't use to do this).
• You're smoking too much.

And this about Present Continuous is taken from here.
The present continuous is used to express repeated or habitual actions in the present that are temporary and may or may not actually be happening at the time of speaking:

• Lucy is taking piano lessons these days.
• Are you still seeing that guy from the hiking club?

Here is the definition for Present Perfect Continuous. It is taken from here.
For temporary habits or situations. The action started in the past and continues to the present in the same way as with use number 1, but we don't answer the questions about 'how long' so clearly. Instead, we use a word like 'recently'.

• I've been going to the gym a lot recently.
• They've been living with his mother while they look for a house.
• I've been reading a lot recently.

And this is from here.
Sometimes the present perfect continuous can emphasise that a situation is temporary.

• I usually go to the gym on the High Street, but it's closed for repairs at the moment so I've been going to the one in the shopping centre.

About Present Perfect Continuous in these videos. Arnel's Everyday English starts at 08:35 or English with Lucy starts at 11:45.

 

[5jj]

In one thread we cannot possiby deal with every use of the two forms that you happen to find. I will just look at your first examples and question

Hello everyone! I do not understand when I should use Present Continuous (PC), and when Present Perfect Continuous (PPC) for temporary or new situations or habits. I don't see the difference between these cases.
Why can not I say these sentences in another tense?

• John's working in a bar until he finds a job in his field. (PC) -> John has been working in a bar until he finds a job in his field. (PPC)

The first of your examples suggests that John's present work is of limited duration. It is not a permanent job. it began at a point in the past (probably not long ago) and will continue until he finds a job in his field. Without context, we don't know whether or not he is in the bar working at the moment of speaking.

In the second, the speaker makes clearer the fact that the duration of the work began at a point in the past and has been ongoing until the moment of speaking. and will continue until he finds a job in his field. As with the first, the suggestion is that the duration of the work is limited, and we don't know whether or not he is in the bar working at the moment of speaking.

In practice there is not a great difference in meaning between the two, though the first focuses on the present moment, and the second on the period up to the present moment. The speaker has free choice between the two forms, depending on the time period they wish to focus on.

 

[emsr2d2]

Alex, please remember to use some/all of the words/phrases/sentences you are asking us to look at as your thread title. Your question or subject matter should appear in the main body of your post only.

 

[Tdol]

Why don't you look at the differences seriously? Charging around finding small things to point out does not make you an expert grammarian, and I am a two-tense person.

 

[=Alex=]

Why don't you look at the differences seriously?

Because I don't see the differences...

 

[Tarheel]

The differences between the two forms can be subtle -- sometimes too subtle to really notice. Which one a speaker or writer chooses to use might come down to habit.

 

[Tdol]

• John's working in a bar until he finds a job in his field. (He might not be working now.)

Does he have another job? Might that not be more important than whether he is at the bar at the time of saying this? I could use this this sentence regardless of whether he is pulling pints or not at the time of speaking. The temporariness is his job, given his ambition, and not the o'clock.

 

[emsr2d2]

Read "John's working at/in/by ..." as "John's employed at/in/by ...".