14.
Text: I'm neglected to tell you an important matter Takahiro-kun. The gateway into your world has opened, and will be closing again within a matter of moments. Unfortunately, if you wish to return to your world, you must leave now.
Problems:
What is `matter` in both `important matter`(1) and `within a matter of moments`(2)? (А почему у вас апостроф вместо кавычек? Это так теперь пишут по-русски?)
Matter 1 - a situation, state, affair, or business:
a trivial matter.

Matter 2 - an amount or extent reckoned approximately:
a matter of 10 miles. Matter | Define Matter at Dictionary.com