used to 表达过去的情况 — 英语词汇题
题目
补全句子：用 used to 表达过去的情况。
1. My grandma ______ (use) to walk to school when she was a child.
2. There used to ______ (be) a small shop near my home.
3. People used to ______ (write) letters, but now they send messages.