Suspend is to temporarily stop (臨時停下來) an activity/event that is currently happening.
Examples:
All children were suspended from school due to the COVID19 pandemic breakout. (which means all children had been in the school before the pandemic, and they had to go their home temporarily)
由於新冠疫情的爆發,孩子們都停課了(孩子們之前一直在學校上課,被迫停下來)
The meeting was suspended because of lunch time.
午餐時間到了,會議臨時停了下來。
Postpone is to move a planned activity/event that has not yet happened to a later date, which means it is in-purpose(有目的的) and reasonable(合理的) action, and this action is initiated(發起) by someone who has enough power to Delay an existing plan.
Examples:
The All-Employee meeting is postponed to next week due to due to the accidental absence of company GM.
公司總經理的缺席導致全體員工大會推遲到下周了。
My boss decided to postpone the project deadline due to the unexpected longer lead time of the key equipment.
由於關鍵設備發貨期超預期太多,我老闆決定推遲項目的驗收日期。
Defer also is to move a planned event to a later date in purpose, but it carries more negative connotation(消極意味).
Example:
The meeting was deferred to next Wednesday.
Delay is a period of time before an event happens. It can be used widely, but it can’t carry voluntary(自願的) (in purpose) connotation(意味), because Delay is unpredictable(不可預知).
Examples:
I was delayed for the morning meeting because of heavy traffic on the way.
早上上班路上堵車嚴重,耽誤了早會(會議並沒有因為我的遲到而停下來)