你好~，希望我的回答对您有所帮助>w<.-Where is our teacher?-He (has gone to) the library.原因如下：has gone to的意思是去了某处，而对话时还他还没有回来。has been to的意思时去过某处，已经从那里回来了。实例：我去过上海，你呢有木有去过？I have been to Shanghai, have you?－王君去哪里了啦？ －噢我想他跑饭店去了吧。-Where's Mr. Wang?-Oh, I suppose he has gone to the restaurant....
