王刚同学在显微镜下观察到一些细胞,他判断为植物细胞.因为他观察到了( )
A:细胞壁和细胞膜
B:细胞壁和叶绿体
C:细胞质和细胞核
D:细胞膜和细胞质
读图“世界某地区等高线图”,完成下题。
— Can you believe _________ little children can finish the difficult problem in _________ a short time?
— I can't believe it until I see it with my own eyes.