a. 勤勉的, 刻苦的

agriculture/agricultural/culture/cultural/industry/industrial/industrious
记忆：
1. agriculture [ 5A^rikQltFE ] agri-culture n. 农业 Agriculture plays a fundamental part in Chinese economy. 在中国经济中农业起着基础的作用。
2. agricultural [ 7A^ri5kQltFErEl ] adj. 农业的 The development of agricultural technology has increase the production greatly. 农业技术的发展大大地提高了生产。
3. culture [ 5kQltFE ] n. 文化 Every nation has its culture, and every one of them is equally colorful and important to another.每个民族有自己的文化，每种文化一样的丰富多彩一样的重要。
4. cultural [5kQltFEr(E)l] adj. 文化的 China suffered too much from the Great Cultural Revolution. 中国在文化大革命中遭受了太多的损失。
5. industry [ 5indEstri ] in-dust-ry 趣味联想：工业里面会产生垃圾，n. 工业，产业, 勤劳 The industry is well developed in the coastal cities.沿海城市工业相当发达。 格言：Industry is fortune's right hand,and frugality her left.勤勉是幸运的右手，世俭是幸运的左手。
6. industrial [ in5dQstriEl ] adj. 工业的，产业的 New industrial revolution will result from his new invention. 他的新发明会引起新的工业革命。
7. industrious [ in5dQstriEs ] adj.勤勉的, 刻苦的 Chinese people is an industrious nation.中华民族是个勤劳的民族。
另类阅读：
China is developing its agriculture as well as industry. As an large agricultural country, it hopes to become an industrial one in the future.