She’s been working for a big company for the last 9 years. (A progressive activity from the past until the present – we focus on the activity that’s been going on for 9 years. It was reasonable to assume that right after this sentence, the speaker will proceed to provide more information in the context of her work in the company and what have been the skills that she’s acquired during her time there etc.)

She has worked for a big company. (Informative\experience – we focus on the fact that she has completed such an action in her lifetime – an achievement in a resume. It is plausible to assume that the speaker will continue describing how this fact makes her into a suitable candidate in a big company. )  

He has been working with Jack for 9 years. (An activity from the past until the present – it is an action he’s been performing from 9 years ago and until now.) 

He has known Jack for 9 years. (A state from the past until the present – even though the word “to know” is a verb, it isn’t an action performed by a person. It is a situation that started 9 years ago and is true until now. )

You haven’t been doing your homework. (A process – the emphasis is on the activity of someone who isn’t doing their homework repeatedly with a result in the present. It is logical to assume that the speaker will proceed to describe how this is going to damage the student’s ability to make progress and succeed at tests. ) 

You haven’t done your homework. (An uncompleted task – we focus on one occurrence that has not been completed and the implication of that in the present. There is a chance the teacher will scold the student on their next lesson.

I have been preparing the food for the past 2 hours. (Task description – the speaker wants to describe the activity and how long it’s been going on. They aren’t interested in providing an informative description of which tasks have been completed and which have not.)

I have prepared the food, called the guests, but haven’t made the cake. (Task completion checklist – informative in nature.)

The cost of living has been increasing steadily for the past year. (A process of change – we focus on the ongoing process of increasing prices. A description from the speaker of how this increase may continue, how it’s problematic and maybe how to stop this process is a sensible follow to this sentence. )

The cost of living has gone up. (Changes – we focus on the result in this case, the prices are now higher and it’s more difficult to get by financially. The speaker may next describe how people have to work longer hours to deal with this change. )

She’s been sitting in class completing the test for the past 2 hours. (An action from the past until the present – we focus on how long the action is and not the number of times it’s happened.)

She has taken the test twice. (How many times something has happened until now – we focus on the number of times she’s taken the test. )

We’ve been moving a lot recently and frankly I’m getting tired of it. (A process taking place recently – the number of times we’ve moved is so large that it has become a form of a progressive action. The emphasis is on the frequent activity that’s happening and how it’s influencing us) 

We have moved into a new neighborhood. (News – a single occurrence is described and its influence on the present. This is informative and has implications in the present – for example, that now letters need to be sent to a different address. )

It smells of food and there are pots on the stove, somebody has been cooking. (Deducing an action has taken place recently, in the past, based on visible signs in the present.) 

I have cooked dinner. Please come to the table. (An action performed in the past that has implications in the present – we focus on the fact that this action has been completed and now something needs to be done in response.)