1) 如果从句所叙述的为真理或不变的事实，则永远用现在时。
At that time, people did not know that the earth moves.
He told me last week that he is eighteen.
2) 宾语从句中的助动词ought, need, must, dare 时态是不变的。
He thought that I need not tell you the truth.
上一篇： 时态与时间状语
下一篇： 现在进行时代替将来时
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国内英语资讯:Real needs of troops-contributing countries must be tended: Chinese envoy
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国内英语资讯:Chinese diplomat calls for U.S. participation in Belt and Road
免费划船游欧洲？只要顺手捡垃圾就可以
从现在开始行动吧
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孕期减肥安全吗?
体坛英语资讯：Fired-up Liu wins second gold in table tennis worlds
国际英语资讯:Czech Republic marks 74th anniversary of end of WWII in Europe
国内英语资讯:China firmly opposes any foreign interference in Hong Kongs affairs: FM spokesperson
国内英语资讯:China makes statement on U.S. planned measures to raise tariffs
农村体重增长居然是全球肥胖率上升的主力军
陌生人寄来的小幸运
What is a True Friend 什么是真正的朋友
国内英语资讯:China sincere towards continuing trade talks with U.S., says FM spokesman
The Real Culture 真正的文化
国内英语资讯:New measures to boost national development zones for further opening up
国际英语资讯:Pompeo hopes Brexit can be resolved soon
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国内英语资讯:Armenian PM to attend Asia civilization dialogue conference in China
英国人为什么总爱道歉？
中餐亦‘咸’亦‘健康’
第八季不是终结 《权游》三部衍生剧即将开拍
国际英语资讯:U.S. House panel votes to hold attorney general in contempt of Congress
My Goal 我的目标
梅根王妃诞下男婴 孩子将有双重国籍