on corn­based foods.

　　C．They showed us how ancient farmers bred corn from a wild grass.

　　D．They offered more information on ancient corn than microfossils of corn.

　　答案：D推理判断题。根据第三段第一句话中的"... microscopic remains that do not offer information on the size and shape of the corncobs"和第二句话"But the newly found corn remains revealed a lot ..."可知，新发现的玉米遗迹能够比玉米微化石提供更多的关于古代玉米的信息。

　　4．What can we know from the last paragraph?

　　A．Remains of ancient corn were found in different places of the world.

　　B．Various kinds of corn were discovered in the new－found corn remains.

　　C．Ancient corncob shapes and kernel colors are quite different from those of today.

　　D．Piperno likes to experiment and grow cool things.

　　答案：B推理判断题。根据最后一段第一句中的"what

　　 surprised Piperno most about the new research was the diversity of corn-from corncob shapes to kernel (玉米粒) colors discovered in the new­found remains"可知B项正确。

　　B