因为there在这里是副词,所以要直接跟在动词be后面用,而第二句中,Beijing是名词,所以不能直接跟在be后面,而是要加介词to.
ever 这个词,常用于否定句和疑问句中,意思是：曾经
Does she ever go outat night?她通常晚上外出吗?
I have not ever been there alone．我从未单独去过那里.
所以这里用得不合适,或者把ever去掉,变成I have been there.或者改成never ：I have never been there.