Large components of traditional Chinese wooden architecture,     1    (include)columns, beams and purlins are often pieced together using sunmao structures. The sun(tenon joint)and the mao(mortise), when interlocked, both support and contain the adjoining parts. This augments stability, and also adds flexibility     2     the architecture. Craftsmen can make and process the     3    (component)in advance and assemble them quickly on site,     4     is simple and efficient. Stability is the most important characteristic of sunmao. Sunmao is the “joint” of a building that absorbs some of the seismic wave by deforming     5    (it), markedly raising earthquake resistance of the entire structure.     6    (similar), sunmao plays its “stabilizer” role to the maximum in furniture. The seat part of a chair     7    (support)by its four legs as well as the cheng under its surface, a smaller supportive upper stick that transforms part of the weight to the downer legs. In this way, the seat could sit in higher weight     8     the entire chair can work longer. Even though every component of the sunmao structure is thin, they can take massive weight by supporting each other. Sunmao is     9     extremely skillful, delicate, and sophisticated invention. This connection method of components     10    (make)ancient Chinese wooden architecture a special flexible structure that surpasses contemporary architectural bents, frames or steel frames.

I volunteered with elephants in South Africa for one month. It was one of the best     1     (month) of my life. It was an eye-opening experience that challenged some of my beliefs on how     2     (vary) animals are used for tourism.

I volunteered with African Elephant Research Unit(AERU)at Knysna Elephant Park. Our daily work would change a bit     3     time to time, but it was mostly made up of cleaning elephant camps, preparing their food and     4     (take) notes on elephant behavior.

I feel our work is useful because AERU is the first research and volunteer program devoted to improving the welfare and     5     (manage) of captive (被圈养的) and wild elephants in South Africa. As people     6     (feed) up with poaching (偷猎), people think it is     7     (good) for elephants to be in captivity than to be in the wild. Before AERU, there was a lack of research on African elephants.

I am a vegan (纯素食者) and lots of misinformation is spread in the vegan community about animal tourism. Most vegans will tell you that you shouldn’t let     8     (you) take part in any tourism activities about animals. However, elephant parks are necessary because of poaching. Many elephant parks cannot run on donations alone. Most of     9     money comes from the tourists     10     want to see these animals close.

Charles Darwin was a geologist and naturalist, fascinated by rocks, plants and animals. He left England on the ship, the Beagle, in 1831. The journey gave him the chance     1     （study）various living things in their natural environments. He noticed that some species of animals were very similar     2     each other.

At that time, people believed that all species had appeared on Earth at the same time, and     3    （change）since. But Darwin began to think differently.

When the ship reached the Galapagos Islands in 1835, it     4    （be）the birds that interested him the most. He suspected that the different     5    （finch）had evolved from a common ancestor,     6     had arrived on the islands a long time before.

It was a     7    （complete）new idea—a theory of evolution. Darwin explained this theory in his book, On the Origin of Species. Many people refused to believe that living things,     8    （include）humans, had evolved from lower forms of life. But Darwin’s scientific studies were so convincing     9     more and more people started to believe his theory.

Today, the book is regarded as one of the most important works ever     10    （write）.