As infants, we can recognize our mothers within hours of birth. In fact, we can recognize the {#blank#}1{#/blank#} of our mother's face well before we can recognize her body shape. It's {#blank#}2{#/blank#} how the brain can carry out such a function at such a young age, especially since we don't learn to walk and talk until we are over a year old. By the time we are adults, we have the ability to distinguish around 100,000 faces. How can we remember so many faces when many of us find it difficult to {#blank#}3{#/blank#} such a simple thing as a phone number? The exact process is not yet fully understood, but research around the world has begun to define the specific areas of the brain and processes {#blank#}4{#/blank#} for facial recognition.

Researchers at the Massachusetts Institute of Technology believe that they have succeeded in {#blank#}5{#/blank#} a specific area of the brain called the fusiform face area (FFA), which is used only for facial recognition. This means that recognition of familiar objects such as our clothes or cars, is from {#blank#}6{#/blank#} in the brain. Researchers also have found that the brain needs to see the whole face for recognition to take place. It had been {#blank#}7{#/blank#} thought that we only needed to see certain facial features. Meanwhile, research at University College London has found that facial recognition is not a single process, but {#blank#}8{#/blank#} involves three steps. The first step appears to be an analysis of the physical features of a person's face, which is similar to how we scan the bar codes of our groceries. In the next step, the brain decides whether the face we are looking at is already known or unknown to us. And finally, the brain furnishes the information we have collected about the person whose face we are looking at. This complex {#blank#}9{#/blank#}is done in a split second so that we can behave quickly when reacting to certain situations.

根据语境，用方框中所给短语的适当形式填空。（每个短语仅使用一次）

Touring Cenotes

    My parents and I traveled to Mexico to visit my grandparents last summer, and we visited the cenotes (say-NO-tays), the natural swimming holes located on the Yucatán Peninsula. The term "swimming hole" might make you think that cenotes are just average, but cenotes are truly {#blank#}1{#/blank#}. I had the most exciting experience of my life exploring these wonders of nature.

    Thousands of years old, the cenotes formed and created sinkholes underneath. Though the ancient Mayans (玛雅人) used the cenotes as water {#blank#}2{#/blank#}, people can now swim, dive, take photographs, and admire local trees and {#blank#}3{#/blank#} life, all through water as clear as liquid diamond.

    In Cenote Azul, my parents, my grandparents, and I swam through water that seemed too blue to be real. I {#blank#}4{#/blank#} countless younger kids diving into the water from a small cliff, but I dared not to jump at first. I finally worked up the courage, and my {#blank#}5{#/blank#} try instantly put all my worries to rest.

    A few days later, we went to Cenote Ponderosa. We stayed in the sun-covered pond, where we {#blank#}6{#/blank#} floated while others did diving and took underwater photographs. Being surrounded by a valley of trees made everything else in the world seem to disappear.

    Grutas de Loltún were definitely the most magnificent of all the cenotes, even though there was no swimming involved. Grutas are caves, and the Grutas de Loltún are among the biggest caves on the entire Peninsula. Our guide, Carolina, walked us through several caves, where we saw many drawings thousands of years old on the cave walls! Just one brief look at those drawings made me feel like I had stepped back in time to a(n) {#blank#}7{#/blank#} era of history. Our group thought Carolina was joking when she claimed she could make the stalagmites(石笋) sing for us, but when she {#blank#}8{#/blank#} them, we heard what sounded like the words "Lol" and "Tun"—the name of the caves! I cannot imagine that a(n) {#blank#}9{#/blank#} played at a concert at Carnegie Hall would have been any better.

    Mexico's Yucatán Peninsula is filled with beauty, but the cenotes are a one-of-a-kind opportunity to commune with nature in a way that is impossible anywhere else on Earth, and I would not {#blank#}10{#/blank#} to do it all again.