在下面一段文字横线处填入语句，衔接最恰当的一项是（    ）

    发展要讲节奏。春生夏长秋收冬藏是自然的节奏，该发芽时发芽，该结果时结果，___________。___________，___________。___________。___________。___________。

①发展要讲成本。农谚讲：谷雨前后，种瓜点豆

②否则就会拔苗助长、竭泽而渔，出现不切实际的“大跃进”

③才有“春种一粒粟，秋收万颗子”

④改革发展也如此，要学会依时而动

⑤这也启示我们发展要遵循规律，不能急于求成

⑥这说的是谷雨节喜雨，种豆育秧正是时候，一旦错过，费时费力，事倍功半

（Ⅰ）求a，b的值；

（Ⅱ）若对任意的t∈R，不等式f（t²﹣2t）+f（2t²﹣k）＜0恒成立，求k的取值范围．

    Diets have changed in China-and so too has its top crop. Since 2011,the country____（grow）more corn than rice. Corn production has jumped nearly 125 percent over____past 25 years, while rice has increased only 7 percent.

    A taste for meat is____(actual) behind the change. An important part of its corn is used to feed chickens, pigs, and cattle. Another reason for corn's rise. The government encourages farmers to grow corn instead of rice____(improve) water quality. Corn uses less water____rice and creates less fertilizer(化肥) runoff. This switch has decreased____(pollute) in the country's major lakes and reservoirs and made drinking water safer for people.

    According to the World Bank, China accounts for about 30 percent of total____(globe)fertilizer consumption. The Chinese Ministry of Agriculture finds that between 2005-when the government ____ (start) a soil-testing program ____ gives specific fertilizer recommendations to farmers - and 2011, fertilizer use dropped by 7.7 million tons. That prevented the emission(排放) of 51.8 million tons of carbon dioxide. China's approach to protecting its environment while ____ (feed) its citizens "offers useful lessons for agriculture and food policymakers worldwide." says the bank's Juergen Voegele.

有人说，人的美丑并不仅仅在于他的外在相貌如何，还在于他如何看待自己，这个观点主要说明人的美丑（  ）