数据库的逻辑数据模型依次有层次、网状、（）和（）关系四种。
后热
You are the desktop administrator for your company. The relevant portion of the company’s network is configured as shown in the exhibit. Bruno is a user in the accounting department. Bruno uses a new Windows XP Professional computer. Bruno reports that he cannot access Web sites on the Internet by using Internet Explorer. However， he can access intranet Web sites that are located on other network subnets by using Internet Explorer. Other users on the network can successfully access Internet Web sites. You need to ensure that Bruno can access Internet Web sites by using Internet Explorer on his computer. What should you do?（） Configure Internet Explorer on Bruno's computer to use the proxy server.。 Configure Internet Explorer on Bruno's computer to permit SSL connections.。 Configure TCP/IP on Bruno's computer to use 192. 168. 10. 57 as the default gateway.。 Configure TCP/IP on Bruno's computer to use 192. 168. 10. 56 for DNS name resolution.。
Which Layer 1 devices can be used to enlarge the area covered by a single LAN segment?（） Switch。 Router。 NIC。 hub。 Repeater。 RJ-45 transceiver。
专业技术人员培养创新能力要注意理论素养的积累，理论素养包括（） 马列主义。 毛泽东思想。 邓小平理论。 "三个代表"重要思想和科学发展观。
柴油发动机可以按照多种方式进行分类，其中四冲程发动机是按哪个分类方式加以区分的（）。
