根据句意及汉语提示填空。
Getting up early is a good _______ (习惯).
Driving carelessly _______ (引起) accidents.
He isn’t at school now. _______ (或许) he is at home.
Xu Xiao taught himself on the _______ (互联网).
We sleep _______ _______ (至少) 8 hours every day.