远动装置中将模拟信号转换成相应的数字量的过程叫（）
A、A/D转换
B、D/A转换
C、标度转换
参考答案：A
I wonder whether the soldier is one of those who _______ abroad to keep peace.
A．has been sent
B．have been sent
C．have sent
D．has sent
潜在水下的潜水艇受______力和______力作用．
