hold on to do ...中的to 是介词吗[如look forward to doing],那这里do是不是要改为doing

hold on to do sth 还是hold on to doing sth hold on to do sth 还是hold on to doing sth hold on to doing sth 还是hold on to do sth We do not have to hold on tightly let hold on to doing 中的to能不能省略? hold on to do ...中的to 是介词吗[如look forward to doing],那这里do是不是要改为doing love makes you hold on to things you shouldn't. hold sb to do Hold on to your hold on to forever hold on to a hold on to the hold on to the hold on to the hold on ,hold up,hold to,hold out分别 hold on to sth hold up to 坚持做某事,是hold on to do sth.还是 hold on to doing sth.有何区别? 有hold on doing这个短语吗不知道有没有这个短语哦,很想知道~hold on to do 和 hold on doing有什么区别?