$1$. Nam used to go to church on Sunday when he was young
$2$. When Barbara was in Italy, she used to stay with an Italian family
$3$. In the past, they used to drive to work
$4$. Mr.Green used to grow Tulips but he doesn't do anymore
$5$. Lot of train used to stop here but nơ they don't do that
`->`used to + V-inf: đã từng làm gì trong quá khứ và bây giờ ko làm nữa
`->`CT: S + used to + V-inf
