题干
给句子排序。
（____）Nice to meet you.
（____）Good morning, Sarah. This is my friend, Amy.
（____）I'm from the USA.
（____）Nice to meet you, too.
（____）Where are you from?
（____）Nice to meet you.
（____）Good morning, Sarah. This is my friend, Amy.
（____）I'm from the USA.
（____）Nice to meet you, too.
（____）Where are you from?
答案(点此获取答案解析）
2,1,4,5,3
”“ 
”表示不同元素的原子。根据图示判断，该反应属于