retain和maintain作“保持”讲怎么区别?

retain和maintain作“保持”讲怎么区别? maintain和retain 有什么区别 remain maintain retain reserve preserve的详细区别 retain 保持微笑retain smile 和 remain smile 哪个正确不用 keep 以上两种说法 请说明一下 keep,remain和retain的区别书上写的注释都是保持,保留.这三个词用法有什么区别? maintain retain 和remain的区别和用法? 单词的辨析retain,remain,maintain,stayretain,remain,maintain,stay的区别是什么?各有什么侧重点?1楼回答的不太明显，还有什么答案呢？ retain和remain的区别是什么? There is little chance that mankind would ___ a nuclear war.a、retain b、edure c、survive d、maintain 谁能帮我解答一道英语六级选择题Critics______that these reforms will lead to a decline in educational standards.A.retain B.maintain C.contain D.obtain It's increasingly difficult to recruit and ___ good staff.A.stay B.reserve C.maintain D.retain 请写出各个词的区别谢谢 求教一道6级单选题Critics____that these reforms will lead to a decline in educational stanards.A retain B maintain C contain D obtain retain是什么意思 英语翻译Population experts predict that if world population continues to grow at the present rate,mankind will soon face a severe challenge to ___ itself in prosperity and peaceA.retain B.maintain C.sustain D.obtain 英语翻译紧急!我要知道,smlie和smlie,and retain smlie中文注解是什么? maintain aspect