You can use suppose or supposing before mentioning a possible situation or action. You usually then go on to consider the effects that this situation or action might have. 假设
verb [vt. 及物动词]推断,料想,猜想;假设,假定,设想;预期,需要,以…为条件;相信,认为(某事物是可能的);(婉转表达)我看,要我说,要不;(因处于某种境地或因约定)必须做(be supposed to do sth.);我看(用于生气地表示预料某事属实)
Suppose someone gave you an egg and asked you to describe exactly what was inside. 假设某人给你一个蛋并要你准确描述里面的东西。