Text One
A. accelerate B. otherwise C. between D.imitate
Phrases:
A. would be difficult to 56
B. from 57 its feathers
C. enabling the bird to 58
D. it 59 could
The emperor penguin traps air in its feathers. Not only does this insulate thebird against extreme cold but it also enables it to move two or three times fasterthan60How Marine biologists have suggested that it does so byreleasing tiny air bubbles 61 .As these bubbles are released, the reduce friction on the surface of the penguin’s wings, 62 .
Interestingly, engineers have been studying ways to make ships go faster byusing bubbles to reduce friction against their hulls (船身 ) . However, researchersacknowledge that further investigation is challenging because "the complexity ofpenguin’s wings 63