【判断题】扫描仪是一种利用光电技术和数字信息技术,以扫描方式将图形或图像信息转换为数字信号的输入设备,光源发出的光线扫描原稿后被反射到一个透镜上,经透镜到CCD上,经D/A转换成数字信号送计算机。
【单选题】光发送机的作用是将()信号转换为光信号。
【单选题】Some parts of the Earth is warm and some are cold because______.
A.
a lot of the heat is reflected
B.
there are clouds and dust in the air
C.
different parts of the Earth receive and reflect different amount of heat
D.
different parts of the Earth have different sources of heat
【单选题】已征出口关税的货物,因故未装运出口,申报退关,经海关查验属实的,纳税人可自缴纳税款之日起( )年内申请退还税款。
【单选题】Some people in parts of the world are wasting food ______ some others haven't any.
【判断题】已征出口关税的货物,因故未装运出口,申报退关,经海关查验属实的,纳税人可以自缴纳税款之日起一年内申请退还税款。( )
【单选题】Some parts of the water are very shallow. But in some places it is very very___________.