Identify meaning relations among sentences

Identify the meaning relation for each of the following pairs of sentences.

a) John is single. John is married. (:vips 7576:)

b) You should see an eye specialist. You should consult an oculist. (:vips 7577:)

c) The president was assassinated. - The president is dead. (:vips 7578:)

d) Take the elevator to the first floor. Take the lift to the ground floor. (:vips 7579:)

e) Mary is younger than John. Mary is older than John. (:vips 7580:)

f) Today is Friday. Today isn't Monday. (:vips 7581:)