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
How does exercise help the elderly?
A、By improving attention.
B、By slowing memory loss.
C、By connecting with others.
D、By controlling cell growth.
While ____ along the shore, I found a lot of sea shells.