no doubt/doubtless/without(a) doubt/undoubtedly
 【问】 There was no doubt that we were unwelcome visitors. (New Concept English，Book 3，L.48)
 毋庸置疑，我们是不受欢迎的来访者。(《新概念英语》(三)，朗文出版公司、世界图书出版公司，1993，P.225)
 许多英汉辞典也都将no doubt译为“无疑地”。例如，《远东英汉大辞典》将You have nodoubt heard the news.译为：“你无疑已听到这消息”。这种译法是否准确?
 【答】 当no doubt用作状语时，我们不应当按其字面意义把它理解为“毋庸置疑”。这种语气太强烈了。请看CGEL(P.623)对no doubt的解释：
 “Doubtless is not synonymous with‘without doubt’. Like no doubt，it in fact implies somedoubt and is synonymous with ‘very probably’.Undoubtedly，on the other hand，expressesconviction.”(“doubtless与‘without doubt’并不是同义的。实际上，doubtless，如同nodoubt一样，都表示某种疑问，因而是与‘very probably’同义的。而undoubtedly则表示深信不疑”)
 LDCE也作了类似的说明：
 “Without doubt and undoutedly express a stronger sense of knowing the real truth than nodoubt or doubtless，which can be used as an adverb meaning not much more than I think or‘I agree.’”
 (“Without doubt和undoubtedly表示了解事实真象的语气比no doubt和doubtless要强，后两者在用作状语时的含义与‘I think’或‘I agree’相差无几。”)
 据此，我们应当将用作状语的without doubt和undoubtedly译为“无疑地”、“毋庸置疑”、“毫无疑问”，而将doubtless和no doubt译为“大概”、“大约”、“可能”、“我想”(probably，I suppose，I think，I agree)：
 1. Without a doubt these theories were all wrong. (Mis)
 毫无疑问，这些理论都是错误的。
 2. You are undoubtedly right. (Neal)
 你无疑是正确的。
 3. It will doubtless rain on the day of the garden party.(LDCE)
 游园会那天很可能下雨。
 4. Mrs. Warren，no doubt，has her merits. (Shaw)
 沃伦太太也许有她自己的优点。
 5. You know him by name，no doubt? (Wilde)
 想必你只是知道他的姓名?
 6. No doubt you can think of others that appeal to you.(AOT)
 我想你是能关心向你求助的人的。
 7. It is no doubt difficult.
 这很可能是困难的。
 不难证明，你前面所提到的《远东英汉大辞典》上的例句似应译为：
 你大概已经听到这个消息了吧。
 而《新概念英语》上的那个句子似可译为：
 看来，我们是不受欢迎的来访者了。