How do I use"I thought"?at Past Tense or Present Tense.
Eg_(1)I thought that was you.
(2)I thought that is you.
(3)I thought he was sick.
(4)I thought he is sick.

Question

How do I use"I thought"?at Past Tense or Present Tense.
Eg_(1)I thought that was you.
      (2)I thought that is you.
      (3)I thought he was sick.
      (4)I thought he is sick.

Answer

Hi Luna

Thought is past tense.

So phrases 1 and 3 are correct.

Please feel free to message me if I can help you further.

Answer

Hey Luna.
If you want to use the word "thought," then (1) and (3) are correct for the past tense. 
Just some extra information, if you would like to change sentences (2) and (4) to present tense, you should change the word "thought" to "think."

Hope this helps.

Answer

The difference between give back and take back is with give back it means you volunteered to give back something. Whereas take back would be it was involuntary taken back by someone or you accepted something back from someone if it was given to you.