为了防止钢铁制品生锈，可采取的措施是 ( )

①涂油 ②刷油漆 ③保持干燥 ④镀上其他金属 ⑤烤蓝 ⑥包塑料布

    A beggar was sleeping in the doorway of a fruit shop. The shop owner felt angry. He walked up to him and 1 him to go away in a rude manner, but the beggar did not seem to2 him and lay still there. The shop owner got much3, shouting that he was a beggar in disguise (假装) and4 cheated passers-by for money by making use of their kindness. At that time, it was the busiest moment of a day and the market was5with shoppers. They all blamed the beggar for6. Showing fear, the beggar7his face in an old blanket. What he received was bitter8rather than help.

    The next morning, it was drizzling. An old man, who went to the market early, found the beggar 9on the ground. He woke the beggar up and 10 asked whether he was cold or not, but the beggar made no 11. Then the old man12his hands gently, saying that they felt13. With these words, he ran home in a hurry, returned with a pile of14, picked out a sweater and urged the beggar to15 it on again and again. Seeing what happened, many other passers-by surrounded the beggar and gave him change one after another, showing16for him. It was not long before the beggar received a handful of 17.

    In many cases our behavior may have a great18 on the people around us because they are likely to19us. Therefore, we should pay special attention to what we do and say, trying to infect others with positive words instead of 20 ones.

阅读下列材料，回答问题：

材料一　明代初年，郑和统率技术上最先进的“宝船”舰队出洋，远至爪哇、印度、非洲之角。郑和下西洋时，欧洲的探险时代尚未开始。……航海期间，郑和每到一地，便宣示中国当朝皇帝的德威，厚赠遇到的君主。

材料二　（清朝时期）外国商人入境中国受到严格限制。与中国的通商是季节性的，仅限于广州一地，且管制甚严。他们不得进入中国内地，种种规章制度专为限制他们的活动范围而定。

──以上材料均摘自【美】基辛格《论中国》

（1）据材料一，指出郑和下西洋的主要目的和影响。

（2）材料二反映了清政府实行的什么政策？其主要表现是什么？​

下列地形区属于我国最大的油菜产区的是（ ）