设z=xcosy-2yex+2x，则
分别为（）。
A:cosy+2yex+2xln2，xsiny-ex B:cosy-2yex-2xln2，xsiny+2ex C:cosy-2yex+2xln2，xsiny-2ex D:siny-2yex+2xln2，xcosy-2ex
One of the most famous scientists to study adaptations (适应能力) was Charles Darwin (达尔文). He was born in England in 1809. He wasn’t the best student in his school, but when he was 16, his father sent him to a medical school. Charles liked spending time outdoors observing (观察) nature more than attending medical classes. He dropped out without graduating.
Next, Charles’ father sent him to school to become a minister (牧师). This time he made it to graduation. But he didn’t want to do the work of a minister. His friends encouraged him to follow his interest in science.
After graduation, Charles was invited to sail on the Beagle as an unpaid scientist. He wasn’t the first choice, but he was the lucky one to go. The Beagle was to travel to South America and then around the world. The crew’s task was to make maps of the places they visited.
On December 27th, 1831, Charles Darwin sailed from England on the Beagle. The trip was planned to last two years. In fact, it lasted five. During this time, he saw many amazing things. He collected lots of plants and animals and took them back to England to study.
Twenty-three years later, Darwin published an scientific paper with another man named Wallace. Darwin described how some animals have adaptations that help them survive. They are passed on to offspring (后代). Darwin’s ideas about adaptations are still very important to the study of living things.
When Darwin published the scientific paper, he was （ ） years old.
A:twenty-three B:twenty-two C:forty-five D:fifty
The (three-fields) system is an agricultural method in which one field (out of) (three) is (left) to lie fallow while the other two fields are being cultivated.
A:three-fields B:out of C:three D:left
The film ______ three hours. It is the longest one i have cver seen.
A:lasted B:stayed C:finished D:ended
One of the most famous scientists to study adaptations was Charles Darwin. He was born in England in 1809. He wasn’t the best student in his school, but when he was 16, his lather sent him to a medical school. Charles liked spending time outdoors observing nature more than attending medical classes. He dropped out without graduating.
Next, Charles’ father sent him to school to become a minister. This time he made it to graduation. But he didn’t want to do the work of a minister. His friends encouraged him to follow his interest in science.
After graduation, Charles was invited to sail on the Beagle as an unpaid scientist. He wasn’t the first choice, but he was the lucky one to go. The Beagle was to travel to South America and then around the world. The crew’s task was to make maps of the places they visited.
On December 27th, 1831, Charles Darwin sailed from England on the Beagle. The trip was planned to last two years. In fact, it lasted five. During this time, he saw many amazing things. He collected lots of plants and animals and took them back to England to study.
Twenty-three years later, Darwin published an scientific paper with another man named Wallace. Darwin described how some animals have adaptations that help them survive. They are passed on to offspring. Darwin’s ideas about adaptations are still very important to the study of living things.
When Darwin published the scientific paper, he was （）years old.
A:twenty-three B:twenty-two C:forty-five D:fifty
One of the most famous scientists to study adaptations (适应能力) was Charles Darwin (达尔文). He was born in England in 1809. He wasn’t the best student in his school, but when he was 16, his father sent him to a medical school. Charles liked spending time outdoors observing (观察) nature more than attending medical classes. He dropped out without graduating.
Next, Charles’ father sent him to school to become a minister (牧师). This time he made it to graduation. But he didn’t want to do the work of a minister. His friends encouraged him to follow his interest in science.
After graduation, Charles was invited to sail on the Beagle as an unpaid scientist. He wasn’t the first choice, but he was the lucky one to go. The Beagle was to travel to South America and then around the world. The crew’s task was to make maps of the places they visited.
On December 27th, 1831, Charles Darwin sailed from England on the Beagle. The trip was planned to last two years. In fact, it lasted five. During this time, he saw many amazing things. He collected lots of plants and animals and took them back to England to study.
Twenty-three years later, Darwin published an scientific paper with another man named Wallace. Darwin described how some animals have adaptations that help them survive. They are passed on to offspring (后代). Darwin’s ideas about adaptations are still very important to the study of living things.
When Darwin published the scientific paper, he was （ ） years old.
A:twenty-three B:twenty-two C:forty-five D:fifty
One of the most famous scientists to study adaptations was Charles Darwin. He was born in England in 1809. He wasn’t the best student in his school, but when he was 16, his lather sent him to a medical school. Charles liked spending time outdoors observing nature more than attending medical classes. He dropped out without graduating.
Next, Charles’ father sent him to school to become a minister. This time he made it to graduation. But he didn’t want to do the work of a minister. His friends encouraged him to follow his interest in science.
After graduation, Charles was invited to sail on the Beagle as an unpaid scientist. He wasn’t the first choice, but he was the lucky one to go. The Beagle was to travel to South America and then around the world. The crew’s task was to make maps of the places they visited.
On December 27th, 1831, Charles Darwin sailed from England on the Beagle. The trip was planned to last two years. In fact, it lasted five. During this time, he saw many amazing things. He collected lots of plants and animals and took them back to England to study.
Twenty-three years later, Darwin published an scientific paper with another man named Wallace. Darwin described how some animals have adaptations that help them survive. They are passed on to offspring. Darwin’s ideas about adaptations are still very important to the study of living things.
When Darwin published the scientific paper, he was （）years old.
A:twenty-three B:twenty-two C:forty-five D:fifty
单选集
