题目

根据上下文或括号里的提示用动词的谓语形式或非谓语形式填空。Sunshine Town is in the north of China. There【1】 lots of things to do in this town. Everybody here is helpful and friendly.【2】 enjoy a good stay in Sunshine Town, you’d better learn some information about it. Sunshine Town is not far from the center of Beijing. It 【3】 (花费) only forty minutes by underground. The air is fresh here. There is also a beautiful park in the center of the town. Look! Some people are【4】 (锻炼) there. There are lots of nice shops in this town. My friend, Sam, o16．如图，AD是△ABC的角平分线，延长AD交△ABC的外接圆O于点E，过C，D，E三点的圆O1交AC的延长线于点F，连接EF、DF．（1）求证：△AEF∽△FED；（2）若AD=8，DE=4，求EF的长．