acknowledge, admit, recognize 和 confess都表示“承認”，但有細微區別。下面我透過英英釋義和舉例來進行區分。acknowledge 意思是 accept the truth of something, admit something承認某事物屬實。著重公開承認某個事實，也指接受或承認某一原則作為約束力、權利。
acknowledge the need for reform 承認改革的需要
a generally acknowledged fact 公認的事實
He acknowledged it to be true/that it was true. 他供認那是事實。
They refused to acknowledge defeat / that they were defeated / themselves beaten. 他們拒不承認失敗 （他們被打敗 / 自己被擊敗）。
He was acknowledged to be the best player. 他被公認是最佳選手。
admit 意思是recognize or acknowledge something as true, often reluctantly; confess something，是承認、供認、招認（常為不情願地）、坦白某事物的意思。admit指的是屈服於外界的壓力或者由於判斷力的驅使不得不承認，帶有不情願的意味，比acknowledge強烈，可與介詞to連用。
George would never admit to being wrong. 喬治從不認錯。
The prisoner has admitted his guilt. 犯人認罪了。
I admit my mistake / that I was wrong. 我承認是我的錯（我錯了）。
I admit (that) you have a point. 我承認你有理。
He admitted having stolen the car. 他招認偷了那輛汽車。
It is now generally admitted to have been (i.e. Most people agree and accept that it was) a mistake. 如今人們公認這是個錯誤。
recognize 意思是be willing to accept somebody / something as valid or genuine; approve, 承認某人(某事物) 有效或屬實, 認可某人或某事物。recognize指正式承認具有某一特殊身份、地位、權利、義務或某一事實存在的合法性。recognize 也含有be prepared to admit or be aware of something或realize 的意思，表示“承認或認清（某事物）”或表示“認識到”的意思
recognize somebody’s claim to ownership 承認某人提出的所有權要求
Britain has recognized (i.e. established diplomatic relations with) the new regime. 英國已承認了這個新政權。
Everyone recognized him to be the lawful heir/as the lawful heir. 大家都承認他為合法繼承人。
I recognized Peter although I hadn’t seen him for 10 years. 雖然我有10年沒有看到Peter了，但我認出了他。
He recognized his lack of qualifications / that he was not qualified for the post. 他承認自己不夠條件[沒有資格]擔任那個職務。
confess 意思是say or admit, often formally (that one has done wrong, committed a crime, etc.) 承認（錯誤﹑ 罪行等）、供認、招認、坦白，常用於對做錯事情的承認。confess也有acknowledge, often reluctantly“承認（常為不情願地）”的意思。
The prisoner refused to confess (his crime). 該犯拒不招供（罪行）。
She finally confessed (to having stolen the money). 她最後招認了（偷了那筆錢）。
He confessed that he had murdered her. 他供認他殺害了她。
She confessed to (having) a dread of spiders, i.e. admitted that she was afraid of them. 她承認她害怕蜘蛛。
I"m rather bored, I must confess. 說老實話, 我真有點厭煩。
He confessed himself (to be) totally ignorant of their plans. 他承認自己對於他們的計劃一無所知。
When the police questioned the man, he confessed. 警察審問這個人時，他坦白了。
acknowledge the need for reform 承認改革的需要
a generally acknowledged fact 公認的事實
He acknowledged it to be true/that it was true. 他供認那是事實。
They refused to acknowledge defeat / that they were defeated / themselves beaten. 他們拒不承認失敗 （他們被打敗 / 自己被擊敗）。
He was acknowledged to be the best player. 他被公認是最佳選手。
admit 意思是recognize or acknowledge something as true, often reluctantly; confess something，是承認、供認、招認（常為不情願地）、坦白某事物的意思。admit指的是屈服於外界的壓力或者由於判斷力的驅使不得不承認，帶有不情願的意味，比acknowledge強烈，可與介詞to連用。George would never admit to being wrong. 喬治從不認錯。
The prisoner has admitted his guilt. 犯人認罪了。
I admit my mistake / that I was wrong. 我承認是我的錯（我錯了）。
I admit (that) you have a point. 我承認你有理。
He admitted having stolen the car. 他招認偷了那輛汽車。
It is now generally admitted to have been (i.e. Most people agree and accept that it was) a mistake. 如今人們公認這是個錯誤。
recognize 意思是be willing to accept somebody / something as valid or genuine; approve, 承認某人(某事物) 有效或屬實, 認可某人或某事物。recognize指正式承認具有某一特殊身份、地位、權利、義務或某一事實存在的合法性。recognize 也含有be prepared to admit or be aware of something或realize 的意思，表示“承認或認清（某事物）”或表示“認識到”的意思recognized (i.e. qualified or official) instructors, schools, charities 獲得承認的教員﹑ 學校﹑ 慈善團體
recognize somebody’s claim to ownership 承認某人提出的所有權要求
Britain has recognized (i.e. established diplomatic relations with) the new regime. 英國已承認了這個新政權。
Everyone recognized him to be the lawful heir/as the lawful heir. 大家都承認他為合法繼承人。
I recognized Peter although I hadn’t seen him for 10 years. 雖然我有10年沒有看到Peter了，但我認出了他。
He recognized his lack of qualifications / that he was not qualified for the post. 他承認自己不夠條件[沒有資格]擔任那個職務。
confess 意思是say or admit, often formally (that one has done wrong, committed a crime, etc.) 承認（錯誤﹑ 罪行等）、供認、招認、坦白，常用於對做錯事情的承認。confess也有acknowledge, often reluctantly“承認（常為不情願地）”的意思。The prisoner refused to confess (his crime). 該犯拒不招供（罪行）。
She finally confessed (to having stolen the money). 她最後招認了（偷了那筆錢）。
He confessed that he had murdered her. 他供認他殺害了她。
She confessed to (having) a dread of spiders, i.e. admitted that she was afraid of them. 她承認她害怕蜘蛛。
I"m rather bored, I must confess. 說老實話, 我真有點厭煩。
He confessed himself (to be) totally ignorant of their plans. 他承認自己對於他們的計劃一無所知。
When the police questioned the man, he confessed. 警察審問這個人時，他坦白了。