两个数字对比，当子项数值和母项数埴差别很（）时，常用倍数或系数表示：差别很（）时，常用千分数表示。
参考答案：小；大
With the development of high technology, more and more new things _______ to the field of IT．
A．have introduced
B．are being introduced
C．were introduced
D．had been introduced
