淀粉的主要种类有（）、绿豆淀粉、小麦淀粉、木薯淀粉、豌豆淀粉、甘薯淀粉、菱角淀粉
参考答案：玉米淀粉
_______ many times , he still couldn’t understand it．
A．Told
B．Having been told
C．He was told
D．Though he had been told
细胞核中有储存________的物质_________，它主要存在于__________中。
