With the development of high technology, more and more new things _______ to the field of IT．

1. A.
   have introduced
2. B.
   are being introduced
3. C.
   were introduced
4. D.
   had been introduced

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

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

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