单项选择题

A．Microwaves are strange electric waves.
B．Microwaves travel in straight lines and do not follow the curve of the earth’s surface.
C．There are not any wires to send microwaves.
D．We must amplify microwaves in relay stations.
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单项选择题
A．She’s spending time going over her accounts.B．She’s been home for only a few days.C．She’s exciting about going home.D．She’s counting the number of vacation days.
A．She’s spending time going over her accounts.
B．She’s been home for only a few days.
C．She’s exciting about going home.
D．She’s counting the number of vacation days.
单项选择题
A．A person who is awake early.B．A bird that catches the worm early in the morning.C．A plane which flies in the morning.D．A communications satellite in orbit round the earth.
A．A person who is awake early.
B．A bird that catches the worm early in the morning.
C．A plane which flies in the morning.
D．A communications satellite in orbit round the earth.
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