三、露西和妈妈在为爷爷的生日挑选礼物，请你从方框中选出合适的词，将对话补充完整。
on presents birthday going to Wednesday
Mum: Hey, Lucy. What day is it today?
Lucy: It's .
Mum: Oh, your grandfather's is coming.
Lucy: When is Grandfather's birthday?
Mum: It's the 18th of September.
Lucy: Really? Grandfather's birthday is on Sunday!
Mum: Yes. We need to buy some for Grandfather.
Lucy: What does Grandfather like?
Mum: Grandfather likes flowers very much. We can buy him some beautiful flowers.
Lucy: That's great. And I'm make a birthday card for Grandfather.

Wednesday；birthday；on；presents；going to

我们结合语境和语法规则逐个匹配词汇：
1. 第一空：问句询问今天是星期几，方框中的Wednesday是表示星期的词汇，符合问题的回答要求。
2. 第二空：对话围绕爷爷的生日展开，此处表达“爷爷的生日快要到了”，birthday意为“生日”，符合语境。
3. 第三空：英语中表示在具体的某一天，要使用介词on，此处接具体日期9月18日，用on符合语法规则。
4. 第四空：句意为“我们需要给爷爷买一些礼物”，some后接可数名词复数，presents意为“礼物”，是复数形式，符合语义。
5. 第五空：此处用到一般将来时的固定结构be going to do sth.，表示打算做某事，表达“我打算给爷爷做一张生日贺卡”的含义，符合用法。