From the Help page:
My Hub was moderated as substandard; what does that mean?
Substandard simply means that the quality of the Hub does not meet HubPages' standards. Below are some common reasons that a Hub may be moderated as substandard:
•"Test" or otherwise unfinished Hubs
•Very little content
•Poorly formatted content
•Content that contains grammar or spelling mistakes that make it difficult to read or understand
•Broken links or videos
Remember that you can always spend some time improving your Hub to meet HubPages standards, and submit it for republication.
I recomend trying to reword things and making sure you are not saying the same thing over and over again with diffrent words.