leave a tip if they were presented with a 'no tip' button"可推知，大部分顾客会按照"没有小费"的标志去做。故选B项。

　　4．What causes the awkwardness between Uber drivers and their customers?

　　A．Customers take advantage of the new gray area for tipping.

　　B．There is no specific policy about tipping from the Uber to follow.

　　C．It's up to customers to decide the drivers' earnings.

　　D．Customers tend to pay least among the three choices.

　　解析：选B　推理判断题。根据第三段和第四段的内容可知，导致优步司机和乘客尴尬的是优步没有明确的小费政策可以遵循。故选B项。

　　B

　　"A wonderful emotion to get things moving when one is stuck is anger. It was anger more than anything else that had set me off, leading to productivity and creativity，" Mary Garden, a Scottish musician, said.

　　Creative people may experience emotions very deeply and strongly, and feel at times they need to shut off or escape from some of them.

　　Sharon M. Barnes is a psychotherapist, serving children, teens and adults with social & emotional needs. She said, "Many highly creative people have emotions and are in touch with their feelings, but they struggle to find their balance emotionally."

　　Sharon once thought about why social and emotional needs are so vital to and yet so difficult for so many highly creative people. She found the answer when talking with one of the painters consulting her. She helped the painter deal with strong emotions connected with the hard times he was going through. "As I was talking with him, a picture suddenly appeared in my head: emotions are much like ocean waves，" she said. "Ocean waves come in many shapes, sizes, speeds and intensities (强度). So do emotions. Ocean waves are influenced by many things including the gravitational pull (万有引力) of the moon, the shape and movement of the ocean floor and the weather. Our emotions are influenced by the gravitational pull of our relationships, the ups and downs of our health and energy, and the 'weather' of the events in our lives." "Sometimes life can seem like the experience of a surfer caught in the 'washing machine'， where he gets caught in wave after wave and can have trouble even coming up for air，" she added.

语篇解读：本文是议论文。有创造力的人总有着强烈的情感，精神治疗医师Sharon很好地诠释了有创造力的人的这种强烈的情感。