People who are new to English often experience confusion about which verb forms can serve as the verb in a sentence. An English sentence must include at least one verb or verb phrase and a tense that relays the time during which the action is taking place. Verbals (such as gerunds and infinitives) should not be confused with verbs.
Correct example: Roger enjoys driving the RV.
Incorrect example: Roger driving the RV.
Correct example: Kyle decided to write a long message.
Incorrect example: Kyle to write a long message.
Past tense correct example: Yesterday, I called you at 5:00 p.m.
Past tense incorrect example: Yesterday, I call you at 5:00 p.m.
Future tense correct example: The next time it rains, I will bring my umbrella.
Future tense incorrect example: The next time it rains, I bring my umbrella.
Present tense correct example: Come in and get warm.
Present tense incorrect example: Come in and got warm.
See Chapter 15 "Sentence Building", Section 15.2 "Choosing Appropriate Verb Tenses" for a more extensive overview of verb tenses.