My friend asked me to meet him outside the cinema . . . . . . . . an hour’s time. A. on B. in C. at D. within

The correct answer is: in.

The preposition “in” is used to indicate a period of time. In this case, the friend asked the speaker to meet him outside the cinema in an hour’s time. This means that the speaker should meet the friend one hour after the friend made the request.

The other options are not correct because they do not indicate a period of time. The preposition “on” is used to indicate a specific day or date. The preposition “at” is used to indicate a specific time. The preposition “within” is used to indicate a period of time that has already begun.

Here are some examples of how the preposition “in” can be used to indicate a period of time:

• I will be back in an hour.
• The meeting will start in 10 minutes.
• I have to finish this project in 2 days.
• The store is open from 9am to 9pm.