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.
After whom was the Amazon River named?
A、The Indian women fighters.
B、The head of an Indian trib
C、The first explorer of the river.
D、The women fighters in ancient Creek stories.
3.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.