In Those Years, We Always Missed It Accidentally

They have known each other since childhood. Their families have known each other for generations. Their parents made an agreement before they were born: if the children of the two families grow up to be a boy and a girl, they will get married. If they are both boys, they will be brothers like their fathers. If they are both girls, they will be the best sisters, just like their mothers! But fate played a trick: his parents gave birth to a pair of twins: a boy and a girl; her parents gave birth to quadruplets - her and his three brothers. She is the youngest, the little princess of the family, and an out-and-out genius since she was a child. One of her three brothers is his identical twin, who is basically exactly the same as her. They have the same personality, hobbies and appearance. If you are not familiar with them, they will almost think that they are the same person. The only difference is that she is a girl, and that one is her favorite brother. His parents and her parents couldn't help but frown when they saw these children, and were very embarrassed, but this did not affect their relationship. His sister liked her brother, and she liked him, which was something the parents were happy to see. However, fate did not seem to let them go. When she was 17 years old, he and his sister went abroad. When he was 19 years old, he returned to China, only to find that she, who he had always expected to see, had also gone to the country he had been to and was studying at the university he had studied. He was disappointed but also excited because his baby had quietly come to him, so he returned to that country - the United States. As for whether they met each other with smiles or tears in the end... Please come and find out in the story!