We must bear in mind when we watch TV or surf the Internet or ta

We must bear in mind when we watch TV or surf the Internet or talk on the phone ___ we are enjoying the fruits of man's labor.
A、as
B、that
C、while
D、because
【正确答案】：B
【题目解析】：考查宾语从句的连接词。此处that we are enjoying the fruits of man's labor when we watch TV or surf the Internet or talk on the phone是宾语从句。