【单选题】—Sorry, I must be off now. —How nice it would be if you ______ a bit longer! [ ]
【判断题】普通光学显微镜下能观察到的最小的细胞内的结构是细胞核。
【判断题】普通光学显微镜下能观察到的最小的细胞内的结构是细胞核 。
【单选题】I would come if I______free tomorrow.
【单选题】As you know, I am a disabled man, but I would be happy if I ___of service to you