Jack used to look nervous when scolded. 请帮忙分析一下这句话的语法

Jack used to look nervous when scolded. 请帮忙分析一下这句话的语法 jack used to get up late.(否定） look like who she used to be还是……what she used to be I used to look just like you怎么理解just Jack used to have a cup of tea Jafter dinner .(改为反义疑问句）Jack used to have a cup of tea Jafter dinner,______ _______? Under no circumstances is Jack to look inside the bag.“look Jack _______ a walk after supper when the weather was fine.A used to take B is used to take C used jack used to wear t-shirts every day 改为一般疑问句 Jack said to me,“you look worried today”Jack said to me,“you “look worried” today”为什么这里不用被动形式啊?“你看起来”不是被看吗? Look,that is our new school building.There _____ old low houses.Look,that is our new school building.There _____ old low houses.A.used to B.used to be C.used to have D.used to having 选择.One day Jack's uncle comes to ____ Jack's parents. A.look B. see C. watch D. look at Look!That is jack .翻译 直接引语Jack said to me ,You look worried today.变为间接引语是什么 英语中to作介词的短语有哪些如look for aword tobe used to when you look ahead to future changes,or think about how the past used to be . Is this the very dictionary one uses to look up new words now?为什么这里用uses to look up?不用 is used to look up? used to used to do改为否定句Jack used to live in a small village with his grandpa.改为否定句印象里不是应该在used和to之间加not吗?为什么答案是didn't use to