in the first sentence of the third paragraph, you have three verbs but just one sentence connector, you should have two, right?
Firstly, the author claimed that many store owners think the use of skateboarding has decreased their business.
let me try.
Firstly, the author claimed that many store owners think that the use of skateboarding has decreased their business.
pay more attention to the use of however, you have to put comma after it.
However(put comma here) it is not reliable to go with the assumptions of some store owners.
A survey for the skateboarders too(also) should be done to ask what brought(bring) them to use the Plaza as a place for skateboarding(put comma here) whether is it because they could not find any other empty place to do the activity or they are just doing this to threaten the owners or customers or empty Plaza enticed(entice) them for skateboarding.
KEEP SPIRIT!!!
Thank you