Grammar
Principal Parts of Regular Verbs
A verb's tenses are made from four basic forms. These forms are called the verb's principal parts.
| Present | Present Participle | Past | Past Participle |
| stop | (am, is, are) stopping | stopped | (has, have, had) stopped |
| ask | (am, is, are) asking | asked | (has, have, had) asked |
The present and the past forms can be used by themselves as verbs.
The present participle and the past participle are always used with a helping verb.