临界期
参考答案：指的是仔鱼从内源营养转向外源营养时，由于饵料保障和仔鱼器官发育两方面不协调而造成仔鱼大量死亡的危险期。
— Look! There's a food shop.
— Yes, we can buy some _____ in it. [ ]
A. bread
B. baseballs
C. clothes
D. books
I don’t know with this problem．It’s too hard．
A．which to do
B．when to do
C．what to deal
D．how to deal
