2015年7月1日，甲公司为向乙公司支付材料款，向乙公司签发了一张出票后3个月付款，

110kV等电位作业时，使用的绝缘操作杆绝缘有效长度不得小于（）m。

A、1.2

B、1.3

C、1.4

D、1.5

（2012）下面所列各种软件中，最靠近硬件一层的是：（）

A.高级语言程序

B.操作系统

C.用户低级语言程序

D.服务性程序

关于髓旁肾单位的特点，正确的是（）

A.分布于肾髓质

B.肾小球体积较小

C.有细长的髓袢

D.无直小血管

E.与尿液的浓缩和稀释功能无关

果蝇是常用的遗传学研究的试验材料，据资料显示，果蝇约有104对基因，现有一果蝇种群，约有107个个体。请回答下列问题：

已知果蝇的正常翅与残翅属于一对相对性状，由一对等位基因控制，残翅（b）为隐性基因，在该种群中每2500只果蝇中才有1只残翅果蝇，那么残翅b基因的基因频率为（）

The other day my brother Tom was beginning his 56.______
motorbike then our neighbor, Mary came out and asked 57.______
him if he was going near the station. So he offered her a lift.
She got at the back of the motorbike and 58.______
they drove away. Just before they reached to the station 59.______
a policeman waved to them to stop. "Excuse me, sir," he said,
"You are not sitting on that motorbike properly. "
"What’s matter with the way I’m sitting" my brother 60.______
asked in surprise. "Not you sir. It’s a young lady," said 61.______
the policeman, "In this country side-saddle(偏座) is not62.______
permitted when one ride a motorbike．”Mary made an excuse 63．______
that she was from Italy，where it isn’t．considering to 64．______
break the law when people take the side-saddle．
The policeman shook head and drove away． 65.______