如图，AB是⊙O的直径，C是⊙O上一点，CD⊥AB，垂足为D，过点B作直线BE∥DC，交AC的延长线于点E．

如图，AB是⊙O的直径，C是⊙O上一点，CD⊥AB，垂足为D，过点B作直线BE∥DC，交AC的延长线于点E．

计算：{#mathml#}$\sqrt{8}-{\left(\mathrm{\pi }-3\right)}^0+{\left(-\frac{1}{3}\right)}^{-1}-\left|-\sqrt{2}\right|${#/mathml#}．

如图，抛物线y={#mathml#}$\frac{1}{2}${#/mathml#}x²+nx﹣2与x轴交于A、B两点，与y轴交于点C，抛物线的对称轴交x轴于点D，已知A（﹣1，0）．

如图，抛物线y={#mathml#}$\frac{1}{2}${#/mathml#}x²+nx﹣2与x轴交于A、B两点，与y轴交于点C，抛物线的对称轴交x轴于点D，已知A（﹣1，0）．

从B栏中找出与A栏相对应的答语。

A                                                                                         B

What does she do? {#blank#}1{#/blank#}                                  A. I was born on May 1^st, 2001.

May I have a look at your present?  {#blank#}2{#/blank#}          B. I'm afraid you can't.

Shall we go to the zoo? {#blank#}3{#/blank#}                            C. She is a student.

When were you born? {#blank#}4{#/blank#}                               D. I want to buy a pair of shoes.

What can I do for you?   {#blank#}5{#/blank#}                           E. Good idea.

从B栏中找出与A栏相对应的答语。

A                                                                                         B

What does she do? {#blank#}1{#/blank#}                                  A. I was born on May 1^st, 2001.

May I have a look at your present?  {#blank#}2{#/blank#}          B. I'm afraid you can't.

Shall we go to the zoo? {#blank#}3{#/blank#}                            C. She is a student.

When were you born? {#blank#}4{#/blank#}                               D. I want to buy a pair of shoes.

What can I do for you?   {#blank#}5{#/blank#}                           E. Good idea.

下图体现哪一科学理论：（    ）

如图①，一次函数y=kx+b的图象与二次函数y=x²的图象相交于A，B两点，点A，B的横坐标分别为m，n（m＜0，n＞0）．

规定sin（α﹣β）=sinα•cosβ﹣cosα•sinβ，则sin15°= {#blank#}1{#/blank#}．