写一个线程A从键盘一次读一个英文句子，线程B、C分别处理这个句子。如果句子为大写字母，则交给C，否则交给B处理。-A written a thread from the keyboard once read an English sentence, thread B, C, respectively, to deal with this sentence. If the sentence is uppercase, then to C, B or else to deal with.