Раскройте скобкиI am trying to describe their experience while they were

1). I am trying to describe their experience while they were away and Im also doing some research on how the gap year has changed their lives.

Present Perfect active voice to show that the gap year is finished, but it has some consequences for the persons lives.  

2). I hope the book will appear in a couple of months.

Future Simple active voice to express the expectations of the book appearance in the future.