单项选择题

The highly efficient modem communication system began ______.

A．over a century ago
B．in the middle 1960s
C．in the late 1980s
D．in the year 1980
<上一题 目录 下一题>
热门 试题

单项选择题
What does brainchild in the paragrapth 4 mean
A．Patent.
B．Invention.
C．Hope.
D．Pride.
单项选择题
What of the following correctly describe Cosmos I
A．It is a 3-ft. metal pod.
B．It has eight 35-ft. metallic wings.
C．It can fly an altitude above 260 miles.
D．When it flies back to Earth, it will fall into pieces.
相关试题