1."I'd" is the abbreviation of "I would":

"I d" is the abbreviation of "I would", which means a hypothesis, wish, suggestion or will. In oral and informal writing, we usually use "I'd" to abbreviate "I would".

If I had more time, I would travel around the world. If I had more time, I would travel around the world. )

Ex 2: I want to have dinner with you. I really want to have dinner with you tonight. )

Ex. 3: He said he would call me back later. He said to call me back later. )

In these example sentences, "I'd" is abbreviated as "I would", indicating a wish, assumption or will.

2. "I'd" is the abbreviation of "I had":

"I d" can also be the abbreviation of "I had", which is mainly used in past hypothetical situations to indicate what happened at a certain moment in the past. This usage usually appears in subjunctive conditional sentences.

If I had known you were coming, I would have been baked into a cake. )

Ex. 2: I had finished my homework before I went to the party. )

In these example sentences, "I d" is abbreviated as "I had", which is used to represent the assumptions in the past and what happened at a certain moment in the past.

Generally speaking, "I d" is a common abbreviation in English, which can stand for "I would" (meaning hypothesis, wish, suggestion or will) or "I had" (used in past hypothetical situations). Knowing these two usages will help us to understand and use this abbreviation form more accurately.