答案：C

考查固定句型。祈使句+连词+陈述句=if条件句，主句；本题上下文是顺接关系，所以使用and;句意：要经常找到方法来表扬你的孩子，你就会发现他们会对你开放内心世界。本题="If" you find ways to praise your children often, you’ll find they will open their hearts to you.