hold tight - hold firmly, usually with one's hands;

oneself自己用 手紧紧的环抱自己

onto 是与人的身体部位时连用的

不具任何实意思。

例如,hit on one,s nose 打在某人的鼻子上

Hold oneself together with sleeping pills

服用安眠药来支持自己

You cannot hold onto yesterday;