以下用于长Q-T间期综合征的药物是（） A.利多卡因 B.莫雷西嗪 C.胺碘酮 D.

If x, y, and z are positive integers and x²=y²+z², which of the following must be true ？（）
Ⅰ.x＞z
Ⅱ.x=y+z
Ⅲ. y²+z² is a positive integer

A. Ⅰ only

B. Ⅱ only

C. Ⅲ only

D. Ⅰ and Ⅱ only

E. Ⅰ and Ⅲ only

根据课文内容用适当的词填空，使短文完整。(一空一词)

    The computer began as a calculating machine in 1642 in France. Then in 1822, it was

built 1.______ an analytical machine, which 2.______ instructions from cards with holes.

In 1936 Alan Turing wrote a book 3.______ (describe) how computers could 4.______ (make)

to work,and built a "universal machine" 5.______ (solve) any mathematical problem.

    At the beginning, the computer was huge, the 6.______ of a large room. 7.______ years

go by, it becomes smaller and smaller, especially 8.______ it got new transistors in the

1960s, it has become smaller and smaller, and 9.______ artificial intelligence, it is

getting cleverer and cleverer, quicker and quicker.

    In 10.______ early 1960s, computers could be connected by a network, 11.______ enables

their users 12.______ information with others and talk to each other. Since computers

13.______ into people's homes, computers are used by billions of people 14.______

information and communicate with each other around the whole world by the 15.______.

可能造成异步电动机空载电流过大的原因有（）。

A、电源电压太高

B、定子绕组匝数不够

C、三角形、Y接线错误

D、电机绝缘老化

下列选项中不属于结构化程序设计原则的是

A．可封装　

B．自顶向下　

C．模块化　

D．逐步求精