Here are the completed key phrases with the provided words:

1. I don’t really **fancy** doing that.
2. I’d **prefer** to ...
3. I’d rather **not**.
4. I’d **rather** ...
5. I think ... **would** be better.
6. I don’t think that’s a **good** idea.
7. Do you fancy **...** ?

Now, let's match them to groups A and B:

**A: Rejecting a suggestion**
- 1 (I don’t really fancy doing that.)
- 3 (I’d rather not.)
- 6 (I don’t think that’s a good idea.)

**B: Suggesting an alternative**
- 2 (I’d prefer to ...)
- 4 (I’d rather ...)
- 5 (I think ... would be better.)
- 7 (Do you fancy ... ?)

Feel free to ask if you need anything else!