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) ."

局部麻醉作用最强的药物是（）

A.普鲁卡因

B.丁卡因

C.利多卡因

D.丙胺卡因

E.布比卡因