CGreek soldiers sent messages by turning their shields (盾) toward the sun. The flashes reflected light could be seen several miles away. The enemy did not know what the flashes meant, but other Greek soldiers could understand the messages.
Roman soldiers in some places built long rows of signal towers. When they had a message to send, the soldiers shouted it from tower to tower. If there were enough towers and enough soldiers with loud voices, important news could be sent quickly over distance.
In Africa, people learned to send messages by beating on a series of large drums (鼓). Each drum was kept within hearing distance of the next one. The drum beats were sent out in a special way that all the drummers understood. Though the messages were simple, they could be sent at great speed for hundreds of miles.
In the eighteenth century, a French engineer found a new way to send short messages. In this way, a person held a flag in each hand and the arms were moved to various positions representing different letters of the alphabet. It was like spelling out words with flags and arms.
Over a long period of time, people sent messages by all these different ways. However, not until the telephone was invented in America in the nineteenth century could people send speech sounds over a great distance in just a few seconds.
第65题:According to this passage, the Roman way of communication depended very much upon.
[A] fine weather
[B] high tower
[C] the spelling system
[D] arm movements
第1题
()是指某一标的本身所具有的足以引起风险事故发生或增加损失机会或加重损失程度的因素。
A.实质风险因素
B.无形风险因素
C.道德风险因素
D.心理风险因素
第2题
()是指某一标的本身所具有的足以引起风险事故发生或增加损失机会或加重损失程度的因素。
A. 实质风险因素
B. 无形风险因素
C. 道德风险因素
D. 心理风险因素
第3题
()是指某一标的本身所具有的足以引起风险事故发生或增加损失机会或加重损失程度的因素。
A.实质风险因素
B.无形风险因素
C.道德风险因素
D.心理风险因素
第4题
某一标的本身所具有的足以引起风险事故发生或增加损失机会或加重损失程度的因素是指()。
A.无形风险因素
B.心理风险因素
C.道德风险因素
D.实质风险因素
第5题
()是指引起或增加风险事故发生的机会或扩大损失幅度的原因或条件。
A.风险因素
B.风险事故
C.风险程度
D.风险幅度
第6题
()是指某一标的本身所具有的足以引起或增加损失机会和加重损失程度的客观原因和条件。
A.道德风险因素
B.实质风险因素
C.心理风险因素
D.综合风险因素
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