1. B need to do
2. C 常常做 某事 但现在不做了, 根据when 后面的动词时态
lived (过去式)决定的
used to / be used to
be used to do的意思是被用来做某事
used to + do:"过去常常"表示过去习惯性的动作或状态,但如今已不存在。
Mother used not to be so forgetful.
Scarf used to take a walk. (过去常常散步)
be used to + doing: 对……已感到习惯,或"习惯于",to是介词,后需加名词或动名词。
He is used to a vegetarian diet.
Scarf is used to taking a walk.(现在习惯于散步)