同工酶是指功能和结构相同的一类酶。()
A. 正确
B. 错误
Glucose-Alanine循环同时解决了因长时间饥饿而产生的NH+4的毒害和对葡萄糖的需要。()
A. 正确
B. 错误
The work of removing stones never ends because ______ .
A. more stones grow in winter
B. the farmers want to start more and more new farms
C. there are so many stones in the thin soil
D. both A and B
The stone walls are used to ______ .
A. prevent their neighbor's cows from coming
B. prevent their own cows from going
C. prevent their neighbors coming
D. build a stone city
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