正確翻譯為：（那時(shí)）我不知道他們可以跟我們下棋.
不屬于否定轉(zhuǎn)移,單純的否定句.
你可以好好了解下否定轉(zhuǎn)移的類型：1．not+think/believe/suppose/imagine…+that－clause（that從句）在這種句式中,not從賓語從句的謂語動(dòng)詞的前面,轉(zhuǎn)移到了主句謂語動(dòng)詞think,believe,suppose等的前面.即（否定前移）例如：e.g.：I'm sorry,but I don't think I know you．對(duì)不起,我想我并不認(rèn)識(shí)你.e.g.：I don't believe he'll come．我想他是不會(huì)來的.這類句子后面的反意疑問句更能準(zhǔn)確地說明not的否定范圍.如：I don't think you've met Xiao Xin,have you?我想你沒遇見小新,對(duì)嗎?在初中范疇,做這類否定轉(zhuǎn)移的反義疑問句的竅門：例句：I don't think you've met Xiao Xin（改成反義疑問句）步驟1：將否定轉(zhuǎn)移掉,原句變?yōu)椋篒 think you haven't met Xiao Xin.步驟2：把I think 無視掉,原句變?yōu)椋篩ou haven't met Xiao Xin .步驟3：按照一般方法,后面加上：have you 上述做題方法在初中范圍內(nèi)95%是能用的.2．not…because（of）這種結(jié)構(gòu)中的 not否定的是后面 because引導(dǎo)的從句或 because of引起的介詞短語.也就是說,not從because（of）的前面轉(zhuǎn)移到了主句或整個(gè)句子的謂語動(dòng)詞的前面.例如：He was not ready to believe something just because Aristotle said so．他并不只是因?yàn)閬喞锸慷嗟抡f過某事如何如何,就輕易相信它.I didn't take a raincoat because it was raining．我不是因?yàn)橄轮瓴艓в暌碌?3．not…+動(dòng)詞不定式或介詞短語在這類結(jié)構(gòu)中,我們實(shí)際上是將否定后面不定式的not轉(zhuǎn)移到了謂語動(dòng)詞上.如：Jack does not seem to like you．（= Jack seems not to like you．）杰克看來不喜歡你.He didn't take the boy from the tracks to safety to win his own fame．but to be nefit the boy's parents．他把男孩從鐵軌上抱到安全地帶,不是為了獲得個(gè)人的名譽(yù),而是為了孩子的父母.He didn't come here by train．他不是乘火車來的.4.never know.you never know how indebted i am for your kindest care and your warmest support.我非常感激你對(duì)我無微不至的關(guān)心和最強(qiáng)大的支持那你怎么知道是單純的否定句還是否定轉(zhuǎn)移呢，再說否定轉(zhuǎn)移里也可以有know呀四個(gè)類型中只有never know，多了一個(gè)never哦