The cat attacked him. The cats attacked him . If you cannot directly count whatever the noun is referring to, don't use an article. Electricity can be dangerous . If you can directly count whatever the noun is referring to but it is plural , don't use an article.
Cats can be dangerous, too .
A cat attacked him with an electric shock . Some blanks will not need articles. Use the flow chart and the above examples as a guide. This was dangerous, because then people were scared to look at any dogs. Then it turned around and looked at him.