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.
Turning off the freeway was our mistake. The secretary's duties are taking minutes and typing letters. You can start this machine by simply pushing this button. His assignment, testing jet planes, is really exciting. In some countries tourists can be arrested for taking pictures.