Sailors on very long sea voyages - months at a time - would get scurvy

Could you help me correct and punctuate the subtitles? (From BBC Learning English)

Here is what I have done:

---------
https://youtu.be/Hw29DuSuy5c?t=60

... in the past sailors on very long sea voyages - months at a time - would get scurvy because they didn't know how to prevent it but you don't ...
--------------
https://youtu.be/Hw29DuSuy5c?t=84

... although these patients also have diabetes, which means you have to watch what you have to be careful, what you eat, so that may be a factor ...
-----------------

https://youtu.be/Hw29DuSuy5c?t=121

so come back - a return of something after a period of time. ...

---------------
https://youtu.be/Hw29DuSuy5c?t=150

Right, so if you've got an example of a comeback concert? I have: Michael Jackson hadn't done any concerts for quite a long time ...
--------------

I have posted it on https://goo.gl/YRJPD9
Why do I post the same question here? Because nobody have responded to that one.