将给定的文本转换成大写字母，并保留特定的单词的小写形式。


原始文本: "The quick brown fox jumps over the lazy dog. This is a sample text for testing."
小写单词: "brown", "the", "is"
转换后的文本: "THE QUICK brown FOX JUMPS OVER THE lazy DOG. this IS a sample text FOR testing."