2) 原因是對那個專業方向不喜歡 - be honest if you are ask. If not, don't mention it.
3) 然後才選到自己喜歡的這個方向的 and got a PHD.
Getting an PDh degree is quite an achievement. They shouldn't be doubting your capability and quaulification, if the job you are applying is in the same field of your phd dgree.
In the US, people respect and understand that you need to find what you like to do. So, it is totally OK to tell them that didn't do well because it was not what you enjoyed to do, or where your passion is... You made the choice of doing something else when you realized it. It is actually good decision making. Hopeful you are not looking for a job using your master degree. :)