Asia has achieved more in controlling the bird flu than Europe in the past few years, _______ the number of people infected with the virus is going up sharply.

       A. when                       B. that                          C. so that               D. where

Asia has achieved more in controlling the bird flu than Europe in the past few years, _______

       the number of people infected with the virus is going up sharply.

       A．when B．that   C．so that      D．where

Asia has achieved more in controlling the bird flu than Europe in the past few years, _______  the number of people infected with the virus is going up sharply.

1. A.
   when
2. B.
   that
3. C.
   so that
4. D.
   where