如图，直线y=﹣ $\frac{1}{2}$ x+1与x轴交于点A，与y轴交于点B，抛物线y=﹣x²+bx+c经过A，B两点．

人们常用“比黄连还苦，比窦娥还冤”这句话形容一个人含冤命苦，你知道窦娥这个艺术形象是谁塑造的吗(      )

⑴Is it hot?____                                                  A. It's on the second floor.

⑵What's the weather like in Beijing?____        B. It's warm and sunny.

⑶Where is the library?____                              C. Yes,we do.

⑷What time is it?____                                      D. No,it isn't.

⑸Do you have a computer room?____            E. It's 6 o'clock.

A．由同种元素组成B.由不同物质组成C.由两种元素组成，其中一种是氧元素D.有一种物质组成E.分子中含有不同种元素的原子

下列关于氨基酸和蛋白质的叙述，错误的是(　 　)