意识形态

某地最近出台一项机动车驾照考试规定；每位考试者一年之内最多有4次参加考试的机会，一旦某次考试通过，使可领取驾照，不再参加以后的考试，否则就一直考到第4次为止。如果李明决定参加驾照考试，设他每次参加考试通过的概率依次为0.6，0.7，0.8，0.9，求在一年内李明参加驾照考试次数ξ的分布列和ξ的期望，并求李明在一年内领到驾照的概率。

某同学称取9.00g淀粉溶于水，测定淀粉的水解百分率。其程序如下

试回答下列问题：

（1）各步加入的试剂为：A_________，B___________，C____________。

（2）加入A溶液而不加入B溶液是否可以______________________，其理由是______________________。

（3）当析出1.44g砖红色沉淀时，淀粉水解率是__________________。[已知葡萄糖与Cu(OH)₂反应的化学方程式为：CH₃OH(CH₂OH)₄CHO＋2Cu(OH)₂ CH₃OH(CH₂OH)₂COOH＋Cu₂O↓＋2H₂O]

按广东农村信用社国际业务对进口业务的规定，以下不属于进口代收业务的主要风险点的是（）

A.手工录入报文信息时，录入要素与真实报文信息不一致

B.该网点不具备受理该业务的权限

C.复核人员、授权人员把关不严，对付款信息审核不仔细导致业务出错

D.付款后申报信息不及时或不正确

Two farmers were on their way home one evening after a hard day’s work. Both were tired. They happened to look up at the sky and saw a black cloud overhead.
"Ah!" said one farmer, "tomorrow we shall have rain and the rice will grow well." The second answered, "Nonsense, the rain will only kill the crops."
So they began to quarrel. Just then a third farmer came along and asked them why they were quarreling. Both farmers explained about the black cloud.
"What cloud" asked the third farmer. They all looked at the sky. The cloud was no longer there.

The two farmers ______ on that day.

A．had a holiday

B．didn’t work

C．worked hard

D．wanted to quarrel with each other

如下所示关系中，关系 T 是由关系 R 和 S 经过______操作得到的。

A．S－R

B．R－S

C．R∩S

D．R∪S