稳定塔设计回流比是（）。A.1：1 B.1.2：1 C.1.5：1 D.2：1
题型：单项选择题
问题：
稳定塔设计回流比是（）。
A.1：1
B.1.2：1
C.1.5：1
D.2：1
题型：单项选择题
阅读理解。
Most animals protect (保护) their young until they are old enough to take care of themselves. A fish
that swims in the rivers of South America protects its
young in a very strange way. This fish, a kind of
catfish, uses its mouth to keep its babies from danger.
When this catfish lays (产下) its eggs, it carries them in its mouth. From what we know, it does not
eat during this time. After the eggs hatch (孵化), the fish swims with its young to protect them. It opens
its mouth when danger appears and its young swim inside. They swim out only when it is safe again.
These catfish may have a peculiar way to protect their young, but it seems (似乎) to work.
1. The best title (标题) for this passage is ________.
A. Fish in South America
B. How A Fish Protects Its Young
C. Laying Eggs
D. A Cat That Swims
2. We can guess the young fish are ________.
A. very brave 
B. large
C. yellow and gold
D. small
3. If the young fish were not near their mothers, they would be________.
A. in greater danger
B. sadder
C. happier
D. safer
4. The word "peculiar" in the last line means________.
A. easy
B. strange
C. useless
D. dangerous