i need help on a thesis statement?

So the current (present perfect) meaning of the verb is:

The children “became” at an unknown time in the past OR they became and are still becoming.

If you take away the “have”, you change the verb to a different tense, thus different meaning.

“The children become”

meaning: Became a responsibility right now, in the present

“the children became”

meaning: became a responsibility in the past

“The children had become”

meaning: became a responsibility before something else that happened in the past

“The children have become”

Meaning: became a responsibility during an unknown time in the past OR they became and continue to become

is that the complete sentence? if not, posting the entire thing will help with suggestions…

…and their children became their responsibilities