“主键”不允许取重复值,是指( )。A.实体完整性约束规则 B.引用完整性约束规则

题型:单项选择题

问题:

“主键”不允许取重复值,是指( )。

A.实体完整性约束规则

B.引用完整性约束规则

C.用户自定义完整性约束规则

D.数据完整性约束规则

考点:计算机等级考试VISUALFOXPRO二级VISUALFOXPRO笔试365
题型:单项选择题

--- He didn’t come to school yesterday, didn’t he ?

--- _________.He was ill in bed.

A.Yes, he did

B.No, he didn’t

C.Yes, what a pity

D.No, I think

题型:单项选择题

2007年世界政坛更迭频繁。5月________就任法国总统;6月________继任英国首相;9月________当选日本新首相;12月________成为韩国新一任总统。[ ]

A.希拉克、布莱尔、小泉纯一郎、卢武铉

B.普京、布什、默克尔、穆沙拉夫

C.萨科齐、布郎、福田康夫、李明博

D.佩雷斯、帕蒂尔、卡尔扎伊、施罗德

题型:单项选择题

化学渗透假说解释()。

A.氨基酸转变为糖类分子

B.糖酵解过程淀粉分子分解为葡萄糖分子

C.捕获的能量在ATP分子中

D.用光作为能源合成葡萄糖分子

题型:单项选择题

Young girls at high risk for depression appear to have a malfunctioning reward system in their brains, a new study suggests. The finding comes from research that (1) a high-risk group of 13 girls, aged 10 to 14, who were not depressed but had mothers who (2) recurrent depression and a low-risk group of 13 girls with no (3) or family history of depression. Both groups were given MRI brain (4) while completing a task that could (5) either reward or punishment.

(6) with girls in the low-risk group, those in the high-risk group had (7) neural responses during both anticipation and receipt of the reward. (8) , the high-risk girls showed no (9) in an area of the brain called the dorsal anterior cingulated cortex (背侧前扣带皮质), believed to play a role in (10) past experiences to assist learning.

The high-risk girls did have greater activation of this brain area (11) receiving punishment, compared with the other girls. The researchers said that this suggests that high-risk girls have easier time (12) information about loss and punishment than information about reward and pleasure.

"Considered together with reduced activation in the striatal (纹状体的) areas commonly observed (13) reward, it seems that the reward-processing system is critically (14) in daughters who are at elevated risk for depression, (15) they have not yet experienced a depressive (16) ," wrote Ian H. Gotlib, of Stanford University, and his colleagues. " (17) , longitudinal studies are needed to determine whether the anomalous activations (18) in this study during the processing of (19) and losses are associated with the (20) onset of depression," they concluded. The study was published in the April of the Archives of General Psychiatry.

13()

A.after

B.among

C.with

D.during

题型:单项选择题

生殖健康咨询效果评估的基本方法有:()

A、问卷调查

B、个别了解情况

C、召开座谈会

D、考试测验

E、使用电话或开联网

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