ADV [ADVERB before verb]大概;很可能;也许;据推测 If you say that something is presumably the case, you mean that you think it is very likely to be the case, although you are not certain. 大概;很可能;也许;据推测 [vagueness]
Presumably the front door was locked when you came down this morning?.
早上你下楼的时候,前门大概是锁上的吧?
The spear is presumably the murder weapon.
这支鱼叉可能就是凶器。
He had gone to the reception desk, presumably to check out.