如图，一玻璃工件的上半部是半径为R的半球体，O点为球心；下半部是半径为R、高为2R的圆柱体，圆柱体底面镀有反射膜．有一平行于中心轴OC的光线从半球面射入，该光线与OC之间的距离为0.6R．已知最后从半球面射出的光线恰好与入射光线平行（不考虑多次反射）．求该玻璃的折射率．

回答有关基因工程的问题：

（1）构建基因工程表达载体时，用不同类型的限制酶切割DNA后，可能产生粘性末端，也可能产生____ 末端．若要在限制酶切割目的基因和质粒后使其直接进行连接，则应选择能使二者产生____ （相同，不同）粘性末端的限制酶．

（2）利用大肠杆菌生产人胰岛素时，构建的表达载体含有人胰岛素基因及其启动子等，其中启动子的作用是____ ．在用表达载体转化大肠杆菌时，常用____ 处理大肠杆菌，以利于表达载体进入：为了检测胰岛素基因是否转录出了mRNA，可用标记的胰岛素基因片段作探针与mRNA杂交，该杂交技术称为____ ．为了检测胰岛素基因转录的mRNA是否翻译成____ ，常用抗原﹣抗体杂交技术．

如果要将某目的基因通过农杆菌传话法导入植物细胞，先要将目睹基因插入农杆菌Ti质粒的____ 中，然后用该农杆菌感染植物细胞，通过DNA重组将目的基因插入植物细胞的____ 上．

    I went hiking to a mountain with my friends last summer． It was a good trip at the beginning but something unexpected happened on the half way．

    One of my friends, Mike, suddenly felt a terrible pain in his stomach and he couldn't move any further． Nobody knew what to do． One girl tried to call her mum with her mobile phone but there was no signal in the mountain area． Luckily I brought medicine with me． After Mike took some, he felt much better． We walked on, and then we all enjoyed ourselves on the top of the mountain.