Money with no strings attached①. It’s not something you see every day②. But at Union Station in Los Angeles last month, a board went up with dollar bills attached to it with pins and a sign that read, “Give What You Can, Take What You Need.”

People quickly caught on. And while many took dollars, many others pinned their own cash to the board. “People of all ages, races, and socio-economic (社会经济的) backgrounds gave and took,” said Tyler Bridges of The Toolbox, which created the project③. “We even had a bride in her wedding dress come up to the board and take a few dollars.” Most of the bills on the board were singles, but a few people left fives, tens and even twenties. The video clip (片段) shows one man who had found a ＄20 bill pinning it to the board.④

“What I can say for the folks that gave the most, is that they were full of smiles,” Bridges said. “There’s a certain feeling that giving can do for you and that was apparent in those that gave the most.” Most people who took dollars took only a few, but Bridges said a very small number took as much as they could.

While the clip might look like part of a new ad campaign, Bridges said the only goal was to show generosity and sympathy. He added that he hopes people in other cities might try similar projects and post their own videos on the Internet.

“After all, everyone has bad days and good days,” he said. “Some days you need a helping hand and some days you can be the one giving the helping hand.”

上面文字摘自2019年浙江高考阅读理解题B，学生遇到几个问题请教老师：

标注①的文字【money with no strings attached】: 请问首句为什么使用一个中心词作为文章开头？这是一种什么语法现象或者修辞现象；

标注②的文字【It’s not something you see every day】: 请问这个句子的主语是否指代前面句子的money with no strings attached?整个句子是否包含着一个定语从句（that）you see every day?

标注③的文字【which created the project】:请问这个非限制性定语从句的先行词是什么？

标注④的文字【the video clip shows one man who had found a $20 bill pinning it to the board】:请问怎样解读这句话的语法成分和中文含义？