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问题 单项选择题

当前数据库技术的发展已形成各种类型的数据库应用技术，下述： Ⅰ．应用的驱动 Ⅱ．多种技术与数据库技术的结合 Ⅲ．关系数据库的研究基础 ( )是这种发展的推动力。

A．Ⅰ

B．Ⅱ

C．Ⅰ和Ⅱ

D．Ⅰ、Ⅱ和Ⅲ

答案

参考答案：D

单项选择题

对许多环境学家来说，植物的灭绝(随之而来的是各种农作物种类不断增加的基因一致性)是环境问题中最严重的一个问题。必须采取行动来阻止野生可食植物及不再耕种的可食植物的减少。否则，基因多样性的缺乏可能引起主要农作物的一大部分在一夜之间被毁掉。例如，在1970年，南方的叶菌病毁坏了大约20%的美国玉米作物，在该疾病所到之处只剩下很少的几种玉米未受影响。 从上段可推知下面哪一选项( )

A．某种植物疾病的易感染性是由基因决定的

B．美国种植的80%的玉米对南方叶菌病有抵抗力

C．野生可食植物的灭绝几乎总是可以追溯到毁灭性的植物疾病(这一原因)

D．植物培养者致力于研究可抵抗植物疾病的植物
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单项选择题

To: salespeople@mangrooveenterprise.com
From: jh@mangrooveenterprise.com
Subject: Sales Meeting
For the last three quarters, our sales have dropped nearly 30 percent. We understand that there is no problem with the quality of the new products recently released, so I believe our sales strategies do (150) something to be desired, and we cannot make excuses. Seeing the first drop should have motivated us to think up better sales strategies and new ideas of how we can increase revenue.
Unfortunately, we have yet to really work towards improving our financial year so far. I, therefore, would like to get you all to (151) feasible ways to help improve the current situation.
Overall, our company has been in a slump for the last year. For this reason, I demand that a meeting (152) this Friday at 2 p.m. Please be on time with your proposals.

A．leave

B．allow

C．let

D．get
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