What are examples of what Sheila and Eric can do without their parents' influence?
-Sheila doesn't know whether she'll marry Gerald anymore and needs time to decide for herself
-Eric says his mother doesn't "understand anything" and that Mr Birlings "not the kind of father a chap could go to" for help
-The family is in a mess and Sheila and Eric refuse to "go on behaving just as we did". They don't want to pretend anymore, showing the parents no longer have authority over their children