A gerund always ends in ing and is used as a noun. Eating is fun. Gerunds can have with them direct objects, predicate nominatives, predicate adjectives or modifiers to form what is called a gerund phrase . Eating is the gerund used as the subject of the verb is . It has its own direct object foods with the adjective solid , which together make up the gerund phrase eating solid foods serving as the subject of the sentence.
Gerunds can be compound.
Fishing is my friend's favorite sport. By adding more water, we can thin the paint. The law forbids shouting fire in a theater. Mr. Jones enjoys his work, collecting and repairing old stereos. My neighbor's pastime is training guard dogs.