What Happens to the Twins in the Twin Paradox with Acceleration?

[Leaping antalope]

My teacher told me that the Twin Paradox is actually a "paradox", it does not follow the rule of SR since it is not an "inertial system", the whole process involves acceleration and deacceration...
What confuses me here is that what will happen to the twins? If SR doesn't apply here, will the twins be the same age after one has been traveling with high speed (almost c) for a long time?

 

[Fredrik]

There are lots of other threads about this (e.g. this one). You should read those first, and ask questions about the things you don't understand in the explanations we've already offered.

 

[Leaping antalope]

Thanks~ I will read them