A.that
B.apple
C.black
D.afternoon

A. they are innocuous agencies
B. they are the causative agents of most human cancer
C. they seem to be infections to many people
D. they are generally thought to be relevant to most cancer in man

A. To tell campus personnel of the new library services.
B. To announce the new movies on campus this summer.
C. To notify university people of important schedule changes.
D. To remind students to validate (使生效) their identification cards.