“惟一的”的英语？

日光透过玻璃屋顶照入; 眼下这是室内惟一的照明.Daylight came in through its glass roof; this was now the only illumination.除了当俘虏之外,惟一的选择就是奋战至死了.The only alternative to being taken prisoner was to die fighting.约翰是她惟一的孩子.John is her only offspri...