Using a non-finite verb form:Lots of parents frankly admit that

Using a non-finite verb form:
Lots of parents frankly admit that they have trouble in bringing up their children.
【正确答案】：Lots of parents frankly admit having trouble in bringing up their children.
【题目解析】：Admit +that从句，表示承认某事实或某事；admit doing sth.表示承认做过某事。