名列“肃州八景”之一的“九眼泉”与嘉峪关的先后关系是（）

请你阅读下面一段歌词，然后根据下面画线两个句子的结构，以“相互就是”开头，仿写两句话。

　　茫茫人海，漫漫大路，你我相遇，成为相互。相互就是：走累了一起扶助；相互就是：走远了一起回顾。啊，相互就是相呼。

　　相互就是_____________；相互就是_____________。啊，相互就是相呼。

如图所示，L₁和L₂为平行的虚线，L₁上方和L₂下方都是垂直纸面向里的磁感应强度相同的匀强磁场，AB两点都在L₂上．带电粒子从A点以初速v与L₂成30°斜向上射出，经过偏转后正好过B点，经过B点时速度方向也斜向上，不计重力，下列说法中正确的是（　　）

A．带电粒子经过B点时的速度一定跟在A点的速度相同

B．若将带电粒子在A点时的初速度变大（方向不变）它仍能经过B点

C．若将带电粒子在A点时初速度方向改为与L2成60°角斜向上，它就不一定经过B点

D．粒子一定带正电荷

患儿男，12岁。胸背部疼痛1天，伴双下肢进行性无力，尿潴留。体检：双上肢肌力5级，双下肢肌力0级，肌张力低，腱反射消失，未引出病理反射。剑突以下深、浅感觉消失，膀胱充盈（脐下2cm），脊柱无叩痛。

首先考虑的治疗是（）

A.神经营养药物

B.大剂量B族维生素

C.甲泼尼龙冲击治疗

D.针灸治疗

E.高压氧治疗

如图是家用除垢净的标签．小明在使用该“除垢净”去除热水瓶中的水垢时，发现有大量气泡产生．联想到水垢的主要成分是碳酸钙，小明猜想“除垢净”的成分中可能有酸．

“威猛先生”牌除垢净   1．主要成分： ______   2．使用说明：加适量水稀释后使用．

（1）水垢属于______（填“纯净物”或“混合物”）；

（2）常见的酸有稀盐酸、稀硫酸，你认为“除垢净”的成分用上述哪一种酸更合适？请将该物质的名称填在图中相应横线上．你不选另一种酸的理由是______；

（3）仔细阅读标签中的使用说明，若使用时不慎将“除垢净”滴在皮肤或衣服上，应立即______．

Beijing: The United States and North Korea had their first (1) in four months here this afternoon as part of the (2) negotiations on how to end North Korea’s nuclear program, but diplomats played clown prospects for (3) . The talks are at the Diaoyutai (4) , a sprawling, garden-filled (5) in western Beijing, with negotiators gathering around a giant hexagonal table built to (6) the six delegations. The Chinese placed the Americans and the North Koreans in (7) , which may have facilitated the (8) between Mr. Kelly and Mr. Kim, which took place (9) in the afternoon session. The two spoke for 30 minutes, two Asian diplomats (10) . The early indications of how the talks are going (11) . A South Korean who took part in the meetings described North Korea as "willing to (12) through dialogue." Chinese officials also put a (13) on the talks. "I heard talks this morning and this afternoon were very successful," the Foreign Minister, Li Zhaoxing, told delegates (14) . But Japanese and Russian participants were (15) . The Russian (16) , Aleksandr Losyukov, described the negotiations as (17) . "So far, the countries have put forward a number of (18) , which are (19) the development of these talks," he told Russian reporters in Beijing. "I would not say that I am feeling (20) ."