问题：
--- Are you worried when your son often plays computer games?
--- Yes. I think playing too many computer games ______ on teenagers.
A．have a good effect
B．has a good effect
C．has a bad effect
D．have a bad effect
--- Are you worried when your son often plays computer games?
--- Yes. I think playing too many computer games ______ on teenagers.
--- Yes. I think playing too many computer games ______ on teenagers.
| A．have a good effect | B．has a good effect |
| C．has a bad effect | D．have a bad effect |
参考答案：