If something happens immediately, it happens without any delay.
He immediately flung himself to the floor.
他立即扑倒在地。
If something is immediately obvious, it can be seen or understood without any delay.
The cause of the accident was not immediately apparent.
这次事故的起因并非即刻可明。
Immediately is used to indicate that someone or something is closely and directly involved in a situation.
The man immediately responsible for this misery is the province's governor.
对这次惨剧负直接责任的人是该省省长。
Immediately is used to emphasize that something comes next, or is next to something else.
They wish to begin immediately after dinner.
他们希望晚饭后马上开始。