In the trapezium（梯形）ABCD，AD∥BC，point E is midpoint（中点）of the AD，point F is midpoint of the BC，EF=（BC-AD），the result of the∠B+∠C is

1. A.
   90°
2. B.
   100°
3. C.
   110°
4. D.
   120°

In the rectangular coordinates，abscissa and ordinate of the intersection point of the lines y=x-k and y=kx+2 are integers for imteger k，then the number of the possible values of k is
（英汉小词典：abscissa横坐标；ordinate纵坐标；intersectionpoint交点；integer整数）

1. A.
   4
2. B.
   5
3. C.
   6
4. D.
   7

In the Rt△ABC，∠ACB=90°，AB+BC+CA=2+，midline for hypotenuse（斜边）is 1，then AC?BC=________．

In the figure1，ABCD is a diamond，points E and F lie on its sides AB and BC respectively，such that=，and△DEFis a regular triangle． Then∠BADis equal to （英汉小词典：diamond菱形；regular triangle正三角形）

1. A.
   40°
2. B.
   60°
3. C.
   80°
4. D.
   100°

In the diagram，the equation of RQ is y=2x-1．If QP is parallel to the x-axis
and the coordinates of P are （8，4），then the distance from P to Q is

1. A.
   4.5
2. B.
   4
3. C.
   5
4. D.
   5.5

If the ratio of the degree of exterior angle of∠A，∠B and∠C that are in the triangle ABC is 5：4：3，then the ratio of the degree of∠A，∠B and∠C is

1. A.
   5：4：3
2. B.
   3：4：5
3. C.
   1：2：3
4. D.
   3：2：1