Please explain why the tense is used in these sentences.

2 The form of the present perfect continuous tense

3 Talk about the uses of the present perfect continuous tense

We sometimes use the Present perfect continuous tense

to talk about actions that started in the past and are still continuing, or have just finished but are still connected to the present in some way.

A I've been waiting for an hour and he still hasn't turned up.

B I'm so sorry I'm late. Have you been waiting long?

Go over Points 1 and 2 on page 9.

4 Exercises on page 9

Answers: (2) have been talking (3) have been taking (4) have been watching

(5) have seen (6) have been writing

5 Compare the present perfect and the present perfect continuous tense

Li Jia has read a book about Stonehenge.

Li Jia has been reading a book about Stonehenge.

In the first sentence, it means the action read isn't still continuing, and Li Jia knows what the book is about now, but in the second sentence , it means the action read is still continuing.

c.f. I've cleaned the house.

I've been cleaning the house.

Read Point 1 on page 10.

Notes:

1)I have visited Egypt twice this month.

I have been touring Egypt for two months.

The present perfect continuous tense can't be used with time expressions such as twice or how many times, because in this tense the action is continuous, not stopped and started again.

We can use the present perfect tense for repeated actions, and the present perfect continuous tense for non-stop actions.