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 sharpen the mind according to Para.2?
A、By increasing the brain siz
B、By decreasing the protein level.
C、By extending the time of concentration.
D、By strengthening brain cells’ connections.
What can we learn about other parents from their remarks in Para. 1?
A、They were indifferent to adult learners.
B、They agreed on the idea of learning chess.
C、They gave congratulations to the adult learner.
D、They thought it odd for an adult to learn chess.