People should be cautious ______their personal information when surfing the Internet so as to prevent certain computer viruses ______ it.

1. A.
   about; to steal
2. B.
   of; stealing
3. C.
   with; to steal
4. D.
   to; from stealing

 People should be cautious ______their personal information when surfing the Internet so as to prevent certain computer viruses ______ it.

. The government is cautious because they are afraid that a new policy on taxation would ______the political balance of the country.

Advertisers are increasingly cautious about taking out ads _______ children, and that is hurting children’s magazines．

1. A.
   being aimed at
2. B.
   aimed at
3. C.
   having aimed at
4. D.
   having been aimed at