工作之间的逻辑关系用( )表示。A．矩形框 B．箭线 C．直线 D．虚线

为改善生态环境，我国“十五”计划要求森林覆盖率从现在的16.5%提高到18.2%，能快速有效地提高森林覆盖率的措施是(       )

①继续营造防护林工程    ②实施退耕还林工程  ③加强自然保护区建设    ④实施天然林保护工程

A．①②

B．③④

C．①③

D．②④

男性，35岁，农民工，食用市售熟肉后1小时感恶心、呕吐、腹痛，伴呼吸困难。查体：意识模糊，双侧瞳孔直径3mm，口唇、面部及四肢末端明显发绀，BP120/76mmHg，HR110次／分，心肺听诊（-）。最可能的是（）

A.有机磷中毒

B.毒鼠强中毒

C.杀虫脒中毒

D.拟除虫菊酯类农药中毒

E.亚硝酸盐中毒

制度创新是人类文明演进的重要组成部分。阅读下列材料，回答问题：

材料一:

春秋之世，灭人之国者，固已为县矣。——《日知录》卷二十二

克敌者，上大夫受县，下大夫受郡。——《左传》哀公二年（公元前493年）

集小都乡邑聚为县，置令、丞、凡三十县——《史记·商君列传》

材料二:

元行省辖区广袤，权力空前，但我们较少看到双方发生矛盾冲突的材料，元灭亡也并非亡于地方的分裂割据……（行省）“不得承制署置属吏”；"诸行省用及千定（锭），必咨都省”；“决大狱，质疑事，皆中书报可而后行”。行省内部实行群官负责和圆署会议制，官员的任用上实行种族交参的原则，这样就在行省官员内部形成互相牵制、分权制衡的状态。在地方区域设置上，这一制度人为的使自然区域隔开，造成犬牙交错的局面，如“合河南河北为一而黄河之险失，合江南江北为一而长江之险失。”

材料四反映的地方行政制度都具有中国特色。运用所学知识，比较它们的主要差异

The TCP protocolis a （1）layer protocol. Each connection connects two TCPs that may be just one physical network apart or located on opposite sides of the globe. In other words, each connection creates a （2） witha length that may be totally different from another path created by another connection. This means that TCP cannot use the same retransmission time for all connections. Selecting a fixed retransnussion time for all connections can result in serious consequences. If the retransmission time does not allow enough time for a （3） to reach the destination and an acknowledgment to reach the source, it can result in retransmission of segments that are still on the way. Conversely, if the retransmission time is longer than necessary for a short path, it may result in delay for the application programs. Even for one single connection, the retransmission time should not be fixed. A connection may be able to send segments and receive （4） faster during nontraffic period than during congested periods. TCP uses the dynamic retransmission time, a transmission time is different for each connection and which may be changed during the same connection. Retransmission time can be made（5） by basing it on the round-trip time (RTT). Several formulas are used for this purpose.

（4）是（）

A.connections

B.requests

C.acknowledgments

D.datagrams

任何空间刚体对于三个互相垂直的坐标来说，都有（）个自由度。

A、2

B、3

C、6

D、9