28．Why was beancurd considered to be liked by the poor?
A. It's easy to make. B. It's easy to cook.
C. It's cheap. D. It's good for health.
答案与解析：C 细节理解题。根据文章第一段Beancurd used to be considered a favourite of the poor because of its low cost.可知。
29．Where can beans grow well?
A. Only in wet soil. B. In dry soil.
C. In soft soil. D. In any soil.
答案与解析：D 细节理解题。根据文章第一段Beans have high yields every year with their short growing period and suitability for various soil both dry and wet.可知。
30．Why did Liu An travel all over the country?
A. He had a dream.
B. He wanted to find something that could make people live longer.
C. He wanted to invent beancurd.
D．He wanted to find gold.
答案与解析：B 细节理解题。根据文章第二段He had a dream of finding the pill for
