答案：填didn't see, was chatting
即：Millie ( didn't see )me at 4:30p.m. yesterday.She ( was chatting )with her friends at that time.
解析：第一个空是一般过去时的否定句,因为句中有明显的过去时间状语yesterday,第二个空是过去进行时,表示当时正在做的事情
翻译：昨天下午4点半,米丽没有看到我,当时她正在和她的朋友聊天.
希望能帮到你,祝更上一层楼O(∩_∩)O
有不明白的请继续追问,可以详谈嘛(*^__^*)