People with a sense of community responsibility are more likely to adhere to the rules and regulations set by
their community, and consciously conduct themselves politely and guard against
such minor offences as making a loud noise, dropping litter, smoking, and
spitting, thus contributing to promoting
the establishment of a harmonious community.
请问句中...contributing to promoting the establishment of a
harmonious community，contributing 和 promoting 哪个是动词？以及为什么是ing形式？
