“日暮思亲友,晤言用自写。”的“写”意思是（)

此题为判断题(对，错)。

A、并、差、选择、投影、连接

B、并、交、选择、投影、笛卡尔积

C、并、差、选择、投影、笛卡尔积

D、并、除、投影、笛卡尔积、选择

A和田籽玉

B、青海玉

C、俄玉

D、韩玉

A韩玉

B、梅岭玉

C、俄玉

D、青海玉

A、逻辑结构设计

B、概念结构设计

C、可行性分析

D、需求分析

automatically each month. You can make payments online with a bank account or use one of the following credit cards (信用卡): Visa, Master Card, Discover Network or American Express. When you make an online payment, please follow the instructions given below.

Instructions

1. To make your payment online, click (点击) the“Pay Now” link under the“Account Overview (概览)”summary.

2. If your business has more than one registered account, first select the account you need from the“Account Number”menu, and then click the“Pay Now”link.

3. If you have never made an online payment before, you will be asked whether you want to make a payment by using a bank account or credit card. Select either “Bank Account” or“Credit Card” from the“Select Payment Method”menu.

The online payment system is available Monday through Saturday, from 7:00 AM to 1 2:00

AM (Midnight) Eastern Time.

1. An AT& T BusinessDirect account helps you _______________.

A. earn an interest from a bank account

B. make the first month’s payment only

C. pay your telephone bill automatically

D. enjoy all the available banking services

2. Tne payment with an AT& T BusinessDirect account can be made online with________.

A. a passport

B. a credit card

C. a driving license

D. a traveller’s check

3. If you have several registered accounts for payment, the first link that you should click is__________.

A. “Select Payment Method”menu

B. “Account Overview” summary

C. the“Account Number”menu

D. the “Pay Now” link

4. When making the first-time online payment, you will be asked to______________.

A. register your online account number

B. open several registered accounts

C. select the payment method first

D. apply for a new credit card

5. The passage is mainly about ___________________.

A. how to pay phone bills by AT& T BusinessDirect

B. how to open an AT& T BusinessDirect account

C. how to make use of online bank services

D. how to start a small online business

A.道家

B.法家

C.儒家

D.佛家

A、πA,B,D(σR.C?S.C(R?S))

B、σR.C?S.C(πA,B,D(R?S))

C、σR.C?S.C(πA,B(R)?πD(S))

D、σR.C?S.C(πD(πA,B(R))?S)

此题为判断题(对，错)。

A 可控制

B 可进入

C 可预测

D 可识别