将给定的文本划分为句子，并输出文本中第五个句子的开头几个单词。
Joe went to the store to buy some milk. He realized he had forgotten his wallet at home. He decided to call his wife to ask for help. When she picked up the phone, he heard a strange voice on the other end.
文本中第五个句子的开头几个单词是： "When she picked up the phone,"