题目

We     writing a letter of complaint to the manager himself．But we'd like to hear your opinion first．        A．have been thinking of             B．had thought of        C．were thinking of               D．thought of 答案：A1．关于倒平板操作，叙述错误的是（　　）A．将灭过菌的培养皿放在火焰旁的桌面，右手拿装有培养基的锥形瓶，左手拔出棉塞B．右手拿锥形瓶，使瓶口迅速通过火焰C．用左手将培养皿打开，右手将锥形瓶中的培养基倒入培养皿，左手缓慢盖上皿盖D．等待平板冷却凝固后，将平板倒过来放置