| must be | estoy seguro | |
| is certainly | sin duda | |
| clearly | evidentemente |
| might be | quizá | |
| could be | es posible | |
| can't be | imposible |
Most school rules rest on an unexamined assumption: that more control produces more learning. The evidence suggests something subtler. Studies indicate that autonomy may improve motivation, although the effect could depend on age and context.