什么是水电机组？

为什么教学是一种特殊的认识活动？

T形接头能承受各种方向的力和力矩，所以应用最为广泛。( )

A little boy invited his mother to attend his school’s first teacher-parent meeting. To the little boy’s (1) , she said she would go. This (2) be the first time that his classmates and teacher (3) his mother and he felt (4) of her appearance. Although she was a beautiful woman, there was a severe sear (疤痕) that (5) nearly the entire right side of her face. The boy never wanted to (6) why or how she got the sear.At the meeting, the people were (7) by the kindness and natural beauty of his mother (8) the sear, but the little boy was still embarrassed (尴尬) and (9) himself from everyone. He did, however, get within (10) of a conversation between his mother and his teacher.The teacher asked (11) ," How did you get the scar on your face"The mother replied, " (12) my son was a baby, he was in a room that caught fire. Everyone was (13) afraid to go in because the fire was (14) , so I went in. As I was running toward his bed, I saw a long piece of wood coming down and I placed myself over him trying to protect him. I was knocked (15) but fortunately, a fireman came in and saved both of us. " She (16) the burned side of her face. "This scar will be (17) , but to this day, I have never (18) what I did. "At this moment, the little boy came out running toward his mother with tears in his eyes. He held her in his arms and felt a great (19) of the sacrifice (牺牲) that his mother had made for him. He held her hand (20) for the rest of the day.

第（18）空应选择（）

A．forgot 

B．recognized 

C．considered 

D．regretted

关于变异系数，下面哪个说法是错误的

A．变异系数就是均数与标准差的比值
B．比较同一人群的身高、体重两项指标的变异度时宜采用变异系数
C．两组资料均数相差悬殊时，不适合用标准差比较其变异程度
D．变异系数没有度量衡单位
E．变异系数的数值有可能大于1

关于控件数组，下列描述中不正确的是 ______。

A．控件数组可由多个控件组成，这些控件具有相同的名字

B．可以通过把两个同类型控件的name属性改成相同值来创建控件数组

C．控件数组中的各元素共用事件，通过index参数来确定是哪一个元素

D．控件数组中的元素可以是不同类型的控件