time reference - During the past week

Please look at the following and tell me what the difference between them is

1. 
   

   During the past week, Chris has answered the phone.

   
   



2. 
   

   During the past week, Chris answered the phone.

   
   

When I say "during the past week' does it mean the week still continues? I mean does it extend up to the present time of speaking? Or has it ended?

When do I use Present perfect and simple past with during?

Also

What is the difference between

3. 
   
   

   In the past week, Chris has answered the phone.

   
   


4. 
   

   In the past week, Chris answered the phone.

   
   

Also is there any difference between past week and last week?

Answer

The present perfect can generally, with few exceptions, only be used with an adverbial of time that includes the moment of speaking.

Meanwhile, the simple past (or: past simple) cannot include an adverbial of time that includes the present. On this point, see When a sentence includes a word like 'today' that indicates present time, can a past form of verb be used?

In

During the past week, Chris has answered the phone.

the time period the past week is not considered to be over when the speaker says this sentence.

In

During the past week, Chris answered the phone.

the time period the past week is considered to be all in the past, i.e., not including the present moment.