题目

Dr. Smith, together with his wife and daughters ,          visit Beijing this summer.              A  is going to   B are going to    C was going to   D  were going to 答案：A 解析: 略10．如图，已知AB是⊙O的直径，AT与⊙O相切于点A，⊙O交BT于C，CT=CB．（1）求证：AB=AT；（2）OT交⊙O于E，求tan∠ABE的值．