B．The activity attracted various people.

　　C．Economic problems were getting worse.

　　D．Young couples needed financial assistance.

　　B　解析：推理判断题。根据第二段的内容，尤其是"People of all ages, races...even had a bride"可推知，作者提到新娘参与该活动来说明参与人员的多样性，故选B项。

　　3．Why did Bridges carry out the project?

　　A．To do a test on people's morals.

　　B．To raise money for his company.

　　C．To earn himself a good reputation.

　　D．To promote kindness and sympathy.

　　D　解析：细节理解题。根据倒数第二段第一句中的"Bridges said the only goal was to show generosity and sympathy"并结合全文内容可知，Bridges开展这个活动的目的在于传递"慷慨和同情之心"，故选D项。

　　B

　　(2019·陕西部分学校第一学期摸底)In the story of The Crow and the Pitcher from Aesop's Fables, a thirsty crow drops stones into a narrow jar to raise the low level of water inside so he can take a drink.

　　Now scientists have evidence to back up that story. Crows actually do understand how to make water displacement(排水量) work to their advantage, experiments show. The results suggest that the birds are, at least in some aspects, as smart as first­graders.

　　Researchers, led by Sarah Jelbert at the University of Cambridge, presented six crows with tubes containing water.Inside the tubes, a worm or a piece of meat on a piece of wood was floating, just out of reach of the crow. In front of the tubes, the researchers arranged several rubber erasers that would sink, and some plastic objects that would float. The crows found out that they could drop the erasers into the tubes in order to raise the water level and get their snack.

However, the__birds__handled__awkwardly in experiments in which they could choose to drop objects in either a wide tube or a narrow one to get a snack, the researchers said. Dropping objects into a narrow tube would lift the water level by a greater amount and put the treat within reach after just two drops; while it took around seven drops to raise the snack to the same level in the wide tube. The crows obviously didn't realize this, and most of them went for the wide tube first.