________ many times, he finally understood it．
A．Told B．Telling C．Having told D．Having been told
________ many times, he finally understood it．
A．Told B．Telling C．Having told D．Having been told
D
考查非谓语的用法。tell与主语之间的关系是被动和完成的关系，所以用having been done来表示被动和完成。