Seeing students so ______ in class is a great encouragement to a teacher.

A.It’s important that we develop a social network when young.
B.To stay healthy, one should have a proper social network.
C.Getting a divorce means risking a reduced life span.
D.We should share our social networks with each other.

A.They have effects similar to those of a marriage.
B.They help develop people’s community spirit.
C.They provide timely support for those in need.
D.They help relieve people of their life’s burdens.