1. 当有人用"How do you do?"进行问候时，一种中规中矩的回答是：同样地问对方"How do you do?"。

2. 另一种回答方式是使用"How are you?"来应对。例如："I'm fine, and how are you?"或者"Pretty good, and how do you do?"。

3. 或者，可以直接用"Nice to meet you."来回应，这是一个非常灵活的回答。

虽然"How do you do?"是以问句的形式表达，但它并不是一个真正的疑问句。它的含义是问候对方，询问对方近况，类似于中国人见面时问"你吃了没有"，其实并不是真的想知道对方是否已经用餐，而是一种见面的寒暄。

一些见面时的常用寒暄语及其回复包括：

1. "How are you?" - "I am great."

2. "How are you doing?" - "Fine, thank you, and you?"

3. "How is your day?" - "It is Very good."

4. "How is everything going these days?" - "everything is going well."

5. "What's up?" - "It is nothing."

6. "How are you going?" - "pretty good."