课时跟踪检测(五) nelson mandela — a modern hero ⅰ.单项填空 1.i caught several fish after four hours, and only then ________ that the secret of success was patience. a.i realized b.i had realized c.did i realize d.had i realized 2.tom said that his uncle had bought an ipad 3 four months before, ________ personally i doubted very much. a.that b.for which