Supposedly, [clause]
置于句首，修饰整个句子。
Supposedly, he is a billionaire.
据说他是个亿万富翁。
据说；据称
据推测；按照某些人的说法；想象上；看上去像；被认为是；恐怕
According to what is believed or claimed by some people, though not necessarily true.
据推测；按照某些人的说法
As a matter of supposition; in the beliefs or according to the claims of some people.
The package supposedly arrived yesterday, but I haven't seen it.
据说包裹昨天就到了，但我还没看到。
用法提示：supposedly 作副词，表示“据说”，说明消息来自他人的说法，不一定可靠。
She is supposedly an expert in French history, though she often gets facts wrong.
据说她是法国历史专家，尽管她经常弄错史实。
用法提示：supposedly 作副词，表示“据称”，强调这是别人的主张而非事实。
The meeting was supposedly postponed, so we stayed home.
据说会议被推迟了，所以我们待在家里。
用法提示：supposedly 作副词，表示“据说”，修饰整个句子，暗示信息未经证实。
置于句首，修饰整个句子。
Supposedly, he is a billionaire.
据说他是个亿万富翁。
置于主语与谓语之间，修饰动词短语。
She supposedly resigned last week.
她据说是上周辞职的。
与 supposedly 基本同义，常可互换；但 allegedly 常暗示指控，supposedly 更中性
较正式，强调自称但可能不实
强调表象与事实可能不符，与 supposedly 侧重点不同
侧重新闻报道，不如 supposedly 通用
grammar · medium
易错句子I am supposedly to finish the report today.
正确表达I am supposed to finish the report today.
误将副词'supposedly'用于'be to'结构，表示'应该'；应使用形容词'supposed'构成'be supposed to'固定搭配。
grammar · medium
易错句子There is a supposedly solution.
正确表达There is a supposed solution.
误将副词'supposedly'用作形容词修饰名词；应使用形容词'supposed'。
Allegedly 用于强调未经证实的宣称，常与法律或指控相关；supposedly 强调普遍认为但未必属实。
Reportedly 用于引述媒体报道；supposedly 用于表示通常认为但无确切证据。
据称安全的
This medicine is supposedly safe for children.
这种药据称对儿童是安全的。
据说容易的
The exam was supposedly easy, but many students failed.
考试据说很容易，但许多学生没通过。
据称简单的
The recipe is supposedly simple, but it took me hours.
这个食谱据称很简单，但我花了好几个小时。
据说免费的
The app is supposedly free, but it has in-app purchases.
这个应用据说免费，但有内购。
据称独立的
The committee is supposedly independent of government influence.
该委员会据称不受政府影响。
据说可靠的
This source is supposedly reliable, but I double-checked the facts.
这个来源据称可靠，但我复核了事实。
与supposedly相关，常表示某事物被声称但未必真实。
与supposedly相关，指未经证实但流传的说法。
与supposedly相关，强调表面现象与实际情况可能不同。
与supposedly相关，指外界普遍认为的印象。
与supposedly相关，因为宣称的事情常引发质疑。
Dictionary facts from ECDICT, WIKTIONARY.