I think there are some significant differences between Verbal Agreement & Oral Agreement. Let’s firstly suppose we take the form of verbal agreement, then we need to consider how the two parties should make the verbal statement on agreement in an official way. This is not easy since many issues including whether the recordings are allowed by the law, who should be the third party witness, and the mutual recognition of a verbal expression of a term used in the conversation, are still undecided. Especially this will lead to a possibly huge trouble when the third issue happens and one party involved rely too much on this statement and find out it is too late and expensive to drop out. But in written format, every word must be formal and has unique and clear meaning under one context that won’t cause divergence in later period. Based on this, the written agreement should be much safer for a contract.