A. Do you like go back in the past?

Yes, I like to go back in the past.

​(Punctuation)

​=> Another way: Your sentence is okay and this is another way of saying it.​

B. The watch is new. Nice

=> Another way: Your sentence is okay and this is another way of saying it.​

This watch is new. It's great. 

This is DolDol's watch.

=> Another way: Your sentence is okay and this is another way of saying it.​

It's Doldol's watch. 

Is this Doldol's watch?

=> Another way: Your sentence is okay and this is another way of saying it.​

Is it really his watch?