@sirgetagrip @David_LKaplan @greg_travis A study of opt-in virtual is perfectly valid, just not entirely generalizable. If kids with motivated parents do well with virtual, that's useful to know.
@sirgetagrip@David_LKaplan@greg_travis一项关于虚拟选择的研究是完全有效的，只是不能完全推广。如果有积极的父母的孩子在虚拟环境中表现良好，了解这一点很有用。