Epidemic diseases usually spread through people’s sneeze, human contact, and ______.

A．One student received a higher grade than he did.
B．He will have to take a number of exams later.
C．The test is more difficult than he expected.
D．Several students in his class have received top*grade.

A．To convince him to go on a canoe trip.
B．To invite him to a cookout.
C．To ask if she can borrow his car.
D．To tell him about a trip she took.