冠心病患者术前应用β-受体阻滞剂，一般是（）。 A.术前2周停用 B.应用至手术当天

点作直线运动，已知某瞬时加速度为a=-2m/s²，t=1s时速度u=2m/s，则t=2s时，该点的速度大小为（）。

A．0

B．-2m/s

C．4m/s

D．无法确定

Shanghai is the biggest city with the largest   1 in the world. It is also the fastest growing city. Its name   2  "on the sea", because it sits on the shores(海滨) of the East China Sea. The  city used to be a fishing town, but these days it is not   3   a major financial(金融的) center, it's also   4  for its art and culture.

5 to Shanghai can be taken from the airport to the center in a fast train. The train     6   more than 430 kin/hour. Once you are in the city, you can't miss a popular area along the Huangpu River. Also, Shanghai Museum is a great place. And if you want to try the local  7  , you should go to Yang's Fried Dumplings. You can get some nice dumplings and a bowl of  8  soup for only ¥ 15.

Now Shanghai is getting very "heavy" from all the growth. As a   9  , the city is going down the soft ground.   10  1921, it has gone down for almost two meters.

患者，男性，64岁，心前区疼痛4h，舌下含服硝酸甘油不缓解急诊入院。心电图示：V₁～V₅导联ST段抬高，弓背向上。实验室检查：血肌酸激酶同工酶增高。该患者的诊断为

A．不稳定型心绞痛
B．急性心肌梗死
C．主动脉夹层动脉瘤破裂
D．心包炎
E．病毒性心肌炎

青岛同亚服装加工企业属于海关B类管理企业，与美国某著名服装公司签订了一批进料执行加工合同。2002年7月4日以电子申报方式向青岛海关申报进口加工服装辅料一批，价值5000美元。次日收货人又向青岛海关递交了纸质报关单。料件进口后，经过6个月的加工，成品于2003年1月返销出口美国。企业于当月月底向海关办理了合同核销手续。
根据上述案例，回答下列问题。

加工贸易合同执行完毕后，经营单位应该持( )到青岛海关办理合同核销手续。

A．进出口货物报关单

B．企业合同核销申请表

C．加工贸易《登记手册》

D．核销核算表

Internet上海台主机都有一个惟一的TP地址。所有的IP地址都为 (15) 位长。IP地址通常被分为 A，B，C，D，E共5类。下列IP地址属于C类地址的是 (16) 。

A．16

B．32

C．48

D．64