题干

若曲线C的参数方程为 {x=2cosθy=1+2sinθ (参数 θ[π
2
π
2
]
),则曲线C(   )

A:表示直线

B:表示线段

C:表示圆

D:表示半个圆

上一题 下一题 0.0难度 选择题 更新时间:2018-05-02 02:44:44

答案(点此获取答案解析)

D

同类题3

阅读下列短文,从文后各题所给的四个选项中选出一个最佳答案。

    Joe Azougar was walking his dog when a bear appeared suddenly.

   "When it came up, the first thing my dog did was1  me and attack the bear, " Azougar said from his 2 in Lady Minto Hospital.

    Then Azougar ran into his house and began to3  his neighbors, warning them what was going on."As I looked around I saw the bear pull my dog into the 4. And to my great sadness, the dog waskilled," he said.

    Then suddenly, the bear 5 and it broke through the house's back window. Azougar began throwing things at the bear and making loud noises. Then he stoodon a chair to make himself look much 6.

    "It seemed as if the bear was very 7 ,  said Azougar.“I thought my best chance was to run outside  8 someone could find me."

    Azougar began running,but the bear  9  him.

    "It had four paws on top of me," he said.“Then, it  10  my body and tried to bite my stomach. That gave me just a few 11  to turn into and protect my head."

    The bear began to pull Azougar's body. “By that time I could feel my body becoming  12," Azougar said.

    Luckily, two women, who were13 , saved him. Their car was such a(n) 14  thing in the bear's eyes, that it ran quickly into the woods.

    "I am just thankful to those two angels that saved me in time," he said.

    People, who have lived here for 20 or 30 years, said they had  15 seenanything like this," said Azougar. He is the first one, and he hopes that he will be also the last one. "Now I'm planning to move somewhere else once I come out of hospital."