[Grammar] what correct tense to use for "during"?

[robjenrobjen]

I am going to make up a few examples with the word, during.

(1a) During the current summer holidays, I have read many books.
(1b) During the current summer holidays, I have been reading many books.

(2a) During the last two years, I have taken many psychology courses.
(2b) During the last two years, I have been taking many psychology courses.

I am very confused about the correct tense to use in these example. Could someone please explain them? Thanks a lot.

 

[Skrej]

They're all correct, but they carry different meanings depending on the verb tense.

Using the Present Perfect (has/have + past participle) means that the action has been completed at some point before the present.
Using the Present Perfect Continuous (has/have + been + present participle) implies that the action started in the past, but is still ongoing at the present.