An exercise about the future tense

Question

Here is an exercise from Interchange 3 by Jack C. Richards.

Complete these predictions with the correct Verb forms( Choose between will, future continuous and future perfect). (More than one answer is possible)

1. Soon they______computers that can translate perfectly from one language to another. (Sell)

2. Within 50 years, people_____ on the moon. (Live)

For #1, I think "will sell" and "will be selling" both work. Perhaps "will be selling" implies that the selling will last some time. Am I correct?

For #2, I am not sure.

Within 50 years, people will have lived on the moon.

Does it mean by any year between 2019 and 2069, people will have lived on the moon and then have returned to the Earth (Living on the moon is finished)

Can "will live" and "will be living" also be used here?

Answer 1

For number 1, I woould choose "will be selling" to indicate that sales of such computers had already started and were continuing as of the viewpoint time. However 'will sell" also works perfectly well.

For number 2, it depends what meaning you want, that is, what prediction is being made. If the prediction is that people will have dwelt on the moon for some time but will no longer do so as of 50 years in the future then one could write

Within 50 years, people will have lived on the moon.

If the prediction is that people start living on the moon less than 50 years from now, and continue, one could write:

• Within 50 years, people will be living on the moon.
• Within 50 years, people will live on the moon.

In this context, there is no significant difference in meaning between these two. One could also make a negative prediction:

• Within 50 years, people will not yet live on the moon.

But I'm not sure that fulfills the terms of the exercise.