4.In each of the following groups of words, there are four underlined letters or letter combinations marked A, B, C and D. Compare the underlined parts and identify the one that is different from the others in pronunciation.
A、cool
B、flood
C、food
D、moon
If John had entered the office ten minutes ago, he____ what we were talking about just now.
A、should know
B、had known
C、would know
D、would have known
What does most research about cats show?
A、They don't need their owners’ attention.
B、They are emotionally attached to their owners.
C、They don't experience separation anxiety as dogs do.
D、They respond to their owners’ voices less than dogs do.