液化石油气罐区的管道阀门及附属装置（）应清理检修一次。

Most of us trade money for entertainment. Movies, concerts and shows are enjoyable but expensive. (78) If you think that you can’t have a good time without spending a lot of money, read on. A little resourcefulness and a few minutes of newspaper-scanning should give you some pleasant surprises.
People may be the most interesting show in a large city. Stroll through busy streets and see what everybody else is doing. You will probably see people from all over the world; you will certainly see people of every age, size, and shape, and you’ll get a free fashion show, too. Window-shopping is also a safe sport-if the stores are closed.
Check the listings in your neighborhood paper. Local colleges or schools often welcome the public to hear an interesting speaker or a good debate. The film or concert series at the local public library probably won’t cost you a penny. Be sure to check commercial advertise-ments too. A flea market can provide hours of pleasant browsing. Perhaps you can find afree cooking or crafts in a department store.
Plan ahead for some activities. It is always more pleasant not to have people in front of you in a museum or at a zoo. You may save some money, too, since these places often seta side one or two free admission days at slow times during the week. (79) Pretend that you are a tourist from time to time, and get to know your city all over again including the indis-pensable (不可错过的) sights that people travel miles to see. If you feel like taking an in-teresting walk, find a free walking tour, or plan one yourself. You will see your city in anew perspective (视角) once you know more about its history or its architectural treas-ures. With imagination and a spirit of adventure you can quite easily find good entertain-ment at no cost at all.

If you are wandering through the busy streets, which will most attract you

A．Various buildings

B．Car driving

C．Window-shopping

D．Free walking

下列组合，错误的是（）

A.硫酸钡--阳性对比剂

B.优维显--离子型对比剂

C.碘必乐--非离子型对比剂

D.二氧化碳--阴性对比剂

E.胆影葡胺--有机碘化物

案例二

[背景材料]

某施工单位承包了一外资工程，报价中现场管理费率为10%，企业管理费率为8%，利润率为5%；A、B两分项工程的综合单价分别为80元/m²和460元/m³。

该工程施工合同规定：合同工期1年，预付款为合同价的10%，开工前1个月支付，基础工程(工期为3个月)款结清时扣回30%，以后每月扣回10%，扣完为止；每月工程款于下月5日前提交结算报告，经工程师审核后于第3个月末支付；若累计实际工程量比计划工程量增加超过15%，支付时不计企业管理费和利润；若累计实际工程量比计划工程量减少超过15%，单价调整系数为1.176。

施工单位各月的计划工作量如表2-1所示：

A、B两分项r程均按计划工期完成，相应的每月计划工程量和实际工程量如表2-2所示：

[问题]

该工程的预付款为多少？

拦网时常采用的步法有（）两种。

由于RRC连接过程建立了Radiolink，在RAB阶段故不用重复建立。