是hold on to doing正确 还是hold to

坚持做某事,是hold on to do sth.还是 hold on to doing sth.有何区别? hold on to do sth 还是hold on to doing sth hold on to doing sth 还是hold on to do sth 坚持做某事是hold on to doing 应该是hold on it还是hold on to it? hold on ,hold up,hold to,hold out分别 hold on to sth hold up to Hold on to your hold on to a hold on to forever hold on to the hold on to 后面是接名词还是动词ing?