题目

下列哪一个细胞里的染色体不成对存在（ ） A．人体的卵细胞                     B．青蛙的受精卵 C．小麦叶的表皮细胞                 D．番茄的果肉细胞 答案：A With the guide ________ the way, we finally got to the village which we were looking for. A. led           B. leading      C. to lead      D. had led