present perfect tense vs simple past tense

Hello,

Teacher: Have you done your homework?
Student: Yes, I have ,but I didn't take it with me.

Can we use present perfect tense and simple past tense together like that?

Thank you...

Sure.
Look at this one:
A: Have you ever been to Japan?
B: Yes, I have been there three times, but my last trip to Japan was really tiring. I just had to focus on my business.
And I'd prefer the student to say: "Yes, I have. But I don't have it with me." or "Yes, I have. But I forgot to take it with me."

aysaa said:

Hello,

Teacher: Have you done your homework?
Student: Yes, I have ,but I didn't take it with me.

Can we use present perfect tense and simple past tense together like that?

Thank you...

Click to expand...

Of course. They are two separate events, and you use the appropriate tense for each.

I think I have understood the difference between each other.

But we can't use them together as I wrote below.

One of my best friends named Jonny has moved to Japan ,but he came back here.

aysaa said:

I think I have understood the difference between each other.

But we can't use them together as I wrote below.

One of my best friends named Jonny has moved to Japan ,but he came back here.

Click to expand...

You're right, that's incorrect.

One of my best friends, named Jonny, has moved to Japan = Jonny still lives in Japan.

One of my best friends, named Jonny, moved to Japan but he came back here = he moved to Japan at some point in the past but then he moved back here.

Concentrate on your placement of commas. Remember that the comma comes directly after a word, then there is a space, then the next word.