\0.4 0.3 0.7 斗地主惩罚照片

Given the problem, we need to determine the fraction of students wearing either glasses or contact lenses.

• The fraction of students wearing glasses is 0.4.
• The fraction of students wearing contact lenses is 0.3. Without additional information about the overlap (students wearing both glasses and contact lenses), we assume that the events are mutually exclusive. This means no one wears both, so we can simply add the fractions. Thus, the fraction of students wearing either glasses or contact lenses is:

Therefore, the fraction of students wearing either glasses or contact lenses is \boxed{0.7}.