4. In a few years' time, the government (is/ will) be able to find a solution to the problem of pollution.
will
6. Astronauts (wasn't/ weren't) able to travel to the moon a century ago.
weren't
5. Three years ago, Sara (won't be able to/ wasn't able to) speak a word of Japanese.
wasn't able to
2. We (were able to/ will be able to) go to the moon for a holiday very soon.
will be able to
1. She is very upset and she (isn't able to/ wasn't able to) to talk to anyone right now.
isn't able to
3. (Will/ Are) you be able to fix the bike?
Will