The risk of epidemics(流行病) may be slightly (high) ______ in crowded urban areas than in rural areas.

A．He plans to go abroad.
B．He plans to start his own business.
C．He plans to work in another hank.
D．He plans to venture with Kitty.

A．Wife and husband.
B．Teacher and student.
C．Clerk and guest.
D．Employer and employee.