x
-3
-2
-1
0
1
2
3
4
y
6
-4
-6
A TV star invited his girlfriend onto his show. He wanted to play a ________ on his girlfriend, but he
fooled himself. [ ]
A. hoax
B. joke
C. play
D. game
酶加速化学反应速度是因为()
A.向反应体系提供能量
B.降低底物的能量水平
C.酶具有活性中心
D.酶对底物有特异性
E.降低反应的活化能