C．The piano she played on.

D．The local music culture.

27．The trip to the Italian Alps helped the author learn to ________．

A．stick to her own passion

B．balance between cultures

C．get rid of her shallowness

D．cherish and protect nature

28．What would be the best title of the text？

A．My Favorite Holiday Memory

B．A Trip Shaping My Personality

C．Lessons from a Foreign Culture

D．My Passion for Music and Nature

C

Athletes who can run several marathons in just months might seem unstoppable. The biggest obstacle（阻碍），it turns out，is their own bodies. A new study find out for the first time a “ceiling” for endurance activities such as long­distance running and biking.

“Physiologists and athletes alike have long been interested in just how far the human body can push itself. When exercising over a few hours，a wealth of evidence suggests most people max out at about five times their basal metabolic（代谢的）rate（BMR）．How humans use energy during longer endurance activities is another question entirely，”says Herman Pontzer，an evolutionary theorist at Duke University，North Carolina.

Pontzer saw an opportunity to answer that question when Bryce Carlson，an endurance athlete and former biochemist at Purdue University，organized the Race Across the USA in