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如图所示，要把直角钢板固定在方钢管上，应采用的连接件是( )

A . 六角螺栓

B . 紧定螺钉

C . 自攻螺钉

D . 膨胀螺栓

血细胞中，数量最多的是（　　），有细胞核的是（　　），体积最小的是（　　）

①红细胞 ②白细胞 ③血小板．

A . ①②③ B . ①③② C . ②③① D . ③②①

商店原有18箱矿泉水，每箱24瓶，现在又运来一些后共有600瓶．又运来的是箱？

下列关于细胞增殖的叙述中，正确的是（）

A . 只有真核细胞增殖才会有DNA的复制 B . 细胞增殖过程中都要形成纺锤体 C . 细胞增殖过程中都有遗传信息的传递和表达 D . 有丝分裂过程中不会发生变异

下列对诗歌艺术手法的判断和分析，不正确的一项是（）

A . 李清照《永遇乐》的“落日熔金，暮云合璧，人在何处？”，选择了“落日”、“暮云”等让人哀伤幽怨的景物，用情景交融的手法表达出作者饱经丧乱后的身世之悲。 B . 苏轼在《水调歌头·黄州快哉亭赠张偓佺》中先用实笔描绘快哉亭下水天相接的景象，接着以“长记”二字带出记忆中“平山堂”的景象，这是虚实结合的手法。 C . 李白的《丁都护歌》中“水浊不可饮，壶浆半成土”等句子使用了白描的手法，写出了纤夫们夏日拖船之苦，令人震撼，同时也体现出诗人关注民生疾苦的可贵情怀。 D . 杜牧的《过华清宫》和白居易的《轻肥》均使用了对比，前者用“一骑红尘”与“妃子笑”，后者用内臣行乐图与江南的“人食人”惨象进行对比，以表达谴责之意。

成语是中华文化中一颗璀璨的明珠。下列成语中源自晋楚争霸的是（　　）

A . 问鼎中原 B . 纸上谈兵 C . 卧薪尝胆 D . 三顾茅庐

阅读下列材料，回答问题。

材料一：第五十四条：中华人民共和国外交政策的原则，为保障本国独立、自由和领土主权的完整，拥护国际的持久和平和各国人民间的友好合作，反对帝国主义的侵略政策和战争政策。

——《中国人民政治协商会议共同纲领》

材料二：我们相信，中印两国的关系会一天一天地好起来。……新中国成立后，就确立了处理中印两国关系的原则，那就是互相尊重领土主权、互不侵犯、互不干涉内政、平等互惠、和平共处的原则。

——《周恩来选集》下卷

材料三：我们并不要求各人放弃自己的见解，因为这是实际存在的反映。但是不应该是它妨碍我们在主要问题上达成共同的协议。我们还应在共同的基础上来相互了解和重视彼此的不同见解。万万亚非人民期待着我们的会议成功。

——周恩来在万隆会议上的讲话

（1）依据材料一，指出新中国成立后奉行的外交政策。
（2）依据材料二，概括中国政府让两国关系“一天天地好起来”的处理原则。结合所学知识，指出该外交原则的国际意义。
（3）依据材料三，周恩来促进“会议成功”的“金钥匙”是什么？综合以上材料概括中国与周边国家交往的特点。
（4）从周恩来经历的以上事件中，他的哪些精神值得我们学习？

地球上最脆弱的生态系统是（）

A . 热带雨林 B . 草原 C . 苔原 D . 沙漠

阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。

Three divers enter a hole leading to a water-filled cave on Mexico's Yucatan Peninsula. They swim for an hour. Finally, they reach a large room 60 feet underground and about the size of two basketball courts. Here, they discover an upside-down human skull. Other bones lie nearby.

The team came across the skull in 2007. The divers then told the Mexican government about the finding. Soon the government formed a team of scientists to look into it. The group, which included archaeologist Dominique Rissolo, believed that the skull belonged to someone who lived in the last ice age. At the ice age some twenty thousand years ago, sea levels dropped and new land appeared. Over time, rain and wind ate holes into some of the land. "The person may have died after entering the cave," Rissolo says. Then, when the ice age ended some ten thousand years ago, sea levels rose. Water flooded the cave, covering the remains.

Worrying that moving the skull might destroy it, scientists decided to examine it at its watery resting place. They collected information about the skull and other pieces of bones. They found that the bones belonged to a 15- to 17-year-old girl who lived at least twelve thousand years ago. The team named her after a type of water nymph(仙女) in Greek myths: the Naiads(Naia).

Naia is the oldest nearly complete human skeleton (骨架) ever found in the Americas. DNA tests showed that she's a direct ancestor of present-day Native Americans. Naia's DNA also matches with people native to Siberia, a part of Russia. Scientists have long thought that ancient people from this area arrived in Alaska during the last ice age. They were the first humans to live in the Americas. And Naia proves how far south they went.

In 2014 the scientists decided to bring up Naia's skull from the cave to protect it from curious divers. So it was taken to a lab, where it remains today.

（1） What can we learn about the skull?

A . It was left alone in the cave. B . It lay under a basketball court. C . It drew the government's attention. D . It was discovered by three scientists.
（2） Why was the skull studied in the cave?

A . Scientists tried to protect it. B . The temperature was fine in there. C . It was against the law to take it out. D . It would help scientists study the cave.
（3） Who were Naia's distant ancestors?

A . Early humans in Greece. B . Early humans in Siberia. C . Early humans in Alaska. D . Early humans in Mexico.