题目

补全对话。根据对话内容，从方框中选出适当的选项补全对话A: Hi, Jenny. Where is my pen? B: Is it on your desk? A: No, it isn't. B: Oh! It's under the teacher's desk. A: B: You're welcome. Oh, I find a ruler here, too. A: No. I think it is Jack's. B: A: OK. A. Is it yours? B. I don't know. C. Thank you for your help. D. Well, I'll ask Jack about it. E. And it's not under my chair.下列关于植物体细胞杂交的叙述，错误的是A. 过程①必须使用纤维素酶和果胶酶去除细胞壁B. 过程①必须用低渗溶液处理以防止酶解时原生质体被破坏C. 过程②可以用离心、振动、电激或PEG来诱导原生质体融合D. 过程④之前进行筛选的目的是为了得到融合的AB杂种细胞