根据所给汉语提示或首字母，写出适当的单词形式，使得句子完整与正确。
71. The college student _____(坚持)that he should be sent to the west, where he was most needed.
72. Are there any ___________ (解释)for your strange behavior?
73. I __________ (真诚地) hope your father will be well again soon.
