VOA慢速英语:Old Style Parenting Starts Debate in the US

unsubstantiated – adj. having no basis in reason or fact

sibling – n. a brother or sister

scared – adj. afraid of something; nervous or frightened

free-range – adj. allowed to move around freely; not kept in cages

constant – adj. happening all the time or very often over a period of time

uncertainty – adj. something that is doubtful or unknown