Can I go to China twice or more than that with the category of M visa .

I went China already on December 13 2014. And i Stay there for 2 weeks and return to my country. And I have the M type. And it is valid for 3 months. It was issued on 1 December 2014 and the enter before is 1 March 2015. So I want to go to China again before it gets expired within the time period. So I don't know whether I can go to China wit it or do I need to have another one.