As a Verb or Adjective:
1. For there to be a large amount or large number of something. English = (be) a lot of, (be) much, (be) many.
2. [Especially with stress] to be a lot of something, more than you really need or more than is necessary. English = (be) plenty, (be) too much, (be) too many.
As Modifier:
1. Used immediately next to a verb to mean that the action happens often or frequently, or to a great extent or degree. English = lots, a lot of the time.