I was quite surprised when I read in your letter that you had decided not to finish your studies at the university.
当我在你的信中看到你已决定终止大学学业时感到很是惊讶。
thereby proving that the burglars had either used skeleton keys or entered over the balcony.
由此可以证明,窍贼或者是用万能钥匙,或者是翻越阳台进来的。