基因突变的可逆性

定语从句的引导词在什么时候可以省略?请分开说. 定语从句有哪些引导词什么时候该用哪个不该用哪个 My heart is very tired.You really pillars You made my heart very painful是什么意思 I say this I really love you I can't bear to see you again that my heart be very painful My heart really they have got some jijce改为否定句 The rain,the intravenous drip down,my heart be very painful. they have some beans.(改为否定句) They have some English stamps改单数 They have got some onions and carrots 改为否定句 关于定语从句引导词的判断如何判断是用关系代词which,who.whose,that这一类词还是用关系副词where,when这一类词?好像是说从句中的一个东西作状语还是怎么地的,怎么判断他是不是状语啊? get,to,the,library,you,can,by,subway连词成句. 我想找些描写塞外生活的诗,文章,了解那里的风俗,生活习惯,有谁知道啊?急用 The problem is difficult.I can't work it out.（连成一句）The problem isn't ___ ___ ___ ___ to work out. the-----is very difficult,I can not work it out用question 还是problem the problem is very difficult.we can't work it out.(合并一个句）the problem isn't_ _ __to work out 谁知道及物动词是什么意思, with the visionphone two people who are talking can see each other中with 能换成哪两个单词?visionphone (视频电话) what do deaf people do when they talk with each other的意思 it's easiest to do sth,It's the easiest----(get)around the city by subwaythe easiest前面到底要不要冠词the? 另外It's the quickest todo sth,有木有这种说法,谢谢1.句中the easiest前面到底要不要冠词the? 2.It's the quickest to Do you remember a time when people were a little nicer,a little softer with each other?I certainly do,and I feel that much of the world has got away from that.1 see such a difference in New York City,for example,from when I first moved here more than It's the easiest----(get)around the city by subway填什么,为什么 the easiest/quickest way to get around the city is going by subway the easiest way to get around the city is going by subway同意词get around 的同意词go sightseeing 还是 trip through 还是walk about 基因属于蛋白质吗基因是蛋白质吗 some dictionaries are in english.这里为什么要用in各路大侠帮帮啦再问下，dictionary for scientists和dictionary for children分别是什么意思啊 Some dictionaries are ( )English and others are ( ) A.at,in B.in,at C,in,in 以nature park为题写一篇英语短文大约80词左右,三克油啦（thank you） 以nature为题的英语短文 以nature为题写一篇英语短文.内容：一、简述人类对大自然的依赖.二、随着人类的发展,生态平衡遭到破...以nature为题写一篇英语短文.内容：一、简述人类对大自然的依赖.二、随着人类的发 利用细菌载体,克隆到一个编码植物光合作用蛋白的基因.证实该基因是否在根或其它非光合作用的组织中表达如何设计实验,写出实验步骤.