28. What is the passage mainly about?
A. Zebra finches over-breed by nature and its consequent ill effects.
B. Only people who love birds can take care of Zebra finches.
C. Domestic zebra finches require a lot of care to live happy lives.
D. Zebra finches never become completely tame.
29. By saying “They are the rabbits of the domestic bird world”，the writer means that both
rabbits and Zebra finches .[来源:Z§xx§k.Com]
A. have good ability to breed
B. are difficult to be raised
C. live delightful lives
D. share responsibilities
30. According to the passage, attributes of domestic zebra finches include —.
A. their rareness and easiness to be tamed *
B. their nest-building，sharing of responsibilities and delightful personalities
C. their in-breeding, which does not cause as much genetic harm as in other species
D. the fact that they are from Australia and have difficulty in adapting themselves [来源:学科网]