Meaning:
Choice of Words:
Meaning: This sentence is about a fish that is currently moving through the water in a lake.
Choice of Words: The word "is" is used to indicate that the fish is currently swimming. The word "swimming" is the present tense of the verb "swim".
Meaning: This sentence is about a fish that was moving through the water in a lake in the past.
Choice of Words: The word "was" is used to indicate that the fish was swimming in the past. The word "swimming" is the past tense of the verb "swim".