1. in/we/ study / past/and/ present/ in/ events / vietnam/ and in / the / world/ history.
⇒We study history events in past and present  in Vietnam and in the world.
2. You/it/ have/ this/ book/ I/ when/ can/ finish.
⇒You can have this book when I finish it.
3. English / English magazines/ by/ reading/ learns/ to /read/ Tuan/.                                          

⇒Tuan learns to read English by reading English magazines.

  XIN CTLHN Ạ!

Answers:

`1)` in/we/ study / past/and/ present/ in/ events / vietnam/ and in / the / world/ history.

$\to$We study history events in past and present in Vietnam and in the world.

`2)` You/it/ have/ this/ book/ I/ when/ can/ finish.

$\to$You can have this book when I finish it.

`3)` English / English magazines/ by/ reading/ learns/ to /read/ Tuan/.

$\to$Tuan learns to read English by reading English magazines.