?T is a built-in type with two variants: some(value) wrapping a value of type T, and none representing absence. Use it when a value might not exist — not because something went wrong, but because there may simply be nothing there:
伊朗经济虽差，但其伊斯兰革命卫队仍具极强的实力
，这一点在新收录的资料中也有详细论述
Россиянам закрыли доступ к Civilization VI и другим играм14:20。关于这个话题，新收录的资料提供了深入分析
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