Read these sentences:

• Rona was eight years old when she saved her siblings from their burning house.

• Rona is now in her twenties.

• Most probably, Rona will have children of her own someday.

The verbs - was, is, will have - in the three sentences above reflect their tense or that quality of a verb that denotes the time when an event happens, happened or will happen.

The three simple tenses indicated above are simple present, simple past, and simple future, respectively.

The simple present tense is used to express an action that is happening now or that happens regularly or continually.

The simple past tense is used to express an action that happened in the past.

The simple future tense is used to express an action that will happen sometime in the future.