---Mr. Wang, I have trouble the text. --- Remember it three times at least.A.to understand; readingB.understanding; readingC.understanding;to readD.to understanding; to read
网友回答
C解析have some trouble in doing sth，第一空用动名词，故将A的排除，根据上下文，可知后文说的是记得曾经做某事，故用动名词，故选