1、keep doing, keep on doing
這兩個詞組均用來表示“不斷做”的意思，但在涵義上有所不同。
keep doing和keep on doing都可表示“不斷（老是）做某事”的意思，強調(diào)動作連續(xù)不斷，每隔一會兒發(fā)生，這時兩者可以換用。不同的是keep doing中的doing是動名詞，作賓語。例如：John always kept (on) asking questions.約翰總是問個不停。News of successes keeps (on) pouring in.捷報頻傳。
keep doing還可表示連續(xù)不斷的動作或持續(xù)的狀態(tài)。keep on doing則沒有這種用法。例如：We kept working in the fields in spite of the rain. 盡管下雨，我們還是堅持在地里干活。Why do the dogs keep barking?這些狗為什么不停地叫？
2、keep sb. from doing sth., keep sth. from sb.
keep sb. from doing sth.相當于prevent (or: stop) sb. from doing sth., 意為"阻止某人做某事"。
keep sth. from sb.則表示“將某事瞞著某人”的意思。例如：What kept you from joining me? 什么事情使你不能和我在一起？We must keep them from getting to know our plans.我們必須防止他們知道我們的計劃。It seems that she keeps something from us.她好像有什么事瞞著我們似的。Why did you keep the truth from me? 你為什么向我隱瞞真相？
3、kind, sort, type
這一組詞都表示“種類”，常可互換使用。
這兩個詞組均用來表示“不斷做”的意思，但在涵義上有所不同。
keep doing和keep on doing都可表示“不斷（老是）做某事”的意思，強調(diào)動作連續(xù)不斷，每隔一會兒發(fā)生，這時兩者可以換用。不同的是keep doing中的doing是動名詞，作賓語。例如：John always kept (on) asking questions.約翰總是問個不停。News of successes keeps (on) pouring in.捷報頻傳。
keep doing還可表示連續(xù)不斷的動作或持續(xù)的狀態(tài)。keep on doing則沒有這種用法。例如：We kept working in the fields in spite of the rain. 盡管下雨，我們還是堅持在地里干活。Why do the dogs keep barking?這些狗為什么不停地叫？
2、keep sb. from doing sth., keep sth. from sb.
keep sb. from doing sth.相當于prevent (or: stop) sb. from doing sth., 意為"阻止某人做某事"。
keep sth. from sb.則表示“將某事瞞著某人”的意思。例如：What kept you from joining me? 什么事情使你不能和我在一起？We must keep them from getting to know our plans.我們必須防止他們知道我們的計劃。It seems that she keeps something from us.她好像有什么事瞞著我們似的。Why did you keep the truth from me? 你為什么向我隱瞞真相？
3、kind, sort, type
這一組詞都表示“種類”，常可互換使用。