题目

完形填空These days，cars are designed using computers. Let’s look at how a new car is created.First，several  1  talk about the new car and any good ideas that they have. Then they sit down at their computers and  2  many sketches. The best two or three drawings are chosen and then more detailed drawings of 3  are developed on the computer. You can change the size，shape or colour of any part on the computer to see  4  the car would look and then you can choose the best design.Both the inside and the outside of the car have to be designed. Part of the inside of the car is  5  如图1，在△ABO中，∠OAB=90°，∠AOB=30°，OB=8．以OB为一边，在△OAB外作等边三角形OBC，D是OB的中点，连接AD并延长交OC于E． （1）直接写出点B的坐标； （2）求证：四边形ABCE是平行四边形； （3）如图2，将图1中的四边形ABCO折叠，使点C与点A重合，折痕为FG，求OG的长．