The other day, I went to a grocery store nearby. It's common to see someone who is homeless or lacking a little1asking people who are walking by for2change. I saw a woman in rags standing in front of the store and I3her, introduced myself to her and asked her4she would like me to get her anything to eat from the Dollar Store. She said she was okay, but was trying to5up for dinner.

    I don't feel6giving money to strangers. I guess it's a social tradition that when you really give money to someone in need, they will7using it for drugs or alcohol or something else that we may not approve of. I didn't8anything to Laura, but just asked her name and9her of my name at that time I felt bad after that10with her because I didn't offer her any help then. Yesterday, I saw her again. I11to go to the nearby grocery store(Safeway), where I got her a grocery gift card. I12by to give it to her13  a big bunch of fresh yellow flowers attached to it. I 14had a chat with her and she was grateful for the15.

    Those people on the streets are often victims or treated as if they don't16 Speaking and giving something to them17a long way. Although it's a difficult and complex issue of knowing what is18 we can just try to help them. We may not be able to help every person19 but if we can help one person from time to time, it does20a lot to the person and we can really make a difference in our world. Be kind and help others. The world will be better.

双氰胺结构简式如图．

（1）双氰胺的晶体类型为 ____．

（2）双氰胺所含元素中， ____ （填元素名称）元素基态原子核外未成对电子数最多．

（3）双氰胺分子中σ键和π键数目之比为 ____

补全对话。