有一些6寸和7寸长的木棍，张华同学从中取出一些接在一起，可 以得到许多长度不同的木棍（不计接头处）．则下列长度的木棍中不能得到的是（　　）　

若集合A={x|3^x＜1}，B={x|0≤x≤1}，则（∁_RA）∩B=（   ）

增加：在缺词处加一个漏字符号（∧）,并在其下面写出该加的词。

删除：把多余的词用斜线（＼）划掉。

修改：在错的词下划一横线,并在该词下面写出修改后的词。

注意：1)每处错误及其修改均限一词;

2)只允许修改10处,多者（从第11处起）不计分。

    Guilin is in Guangxi Zhuang Autonomous Region, China, famous of its mountains and waters. I went here last summer and stayed for five day. During that time not only I enjoy the fascinating scenery like the unique mountains and clean rivers, but also I try the traditional weaving of Zhuang people. That impressed me most was the amazing folk-song-singing competition on the Li River, which attracted thousands of visitors or locals. Guilin enjoys a worldwide fame for it beautiful scenery, so it's well worth visiting. I am strongly recommend you to visit it. I believe you will have a wonderfully time.

部分短周期元素的原子半径及主要化合价．