being on their own forstered帮我分析一下这个句子的结构,

forstered应该写成 fostered吧,是收养的意思.
没有上下文,推测being on their own和fostered应该是共同修饰一个名词,意思是：被人收养,依靠自己生存的.形容词或词组共同修饰一个名词的情况很常见,如：Being the only child of her family,spoiled but lonely,she wanted to find a friend.她是家里的独生女,被父母宠爱却感到孤独,想要找到一位朋友.