Answer:
21) There is a 0% chance of picking a 13 in a deck of cards. Impossible.
If there is a 0% chance that something will happen then it is impossible.
22) There is a 50% chance of picking a red card in a deck of cards. Equally likely.
If there is a 50% chance that something will happen, it is equally likely that it will happen.
23) There is an 80% chance of snow tomorrow. Likely or certain.
If there is an 80% chance of something happening, it means that the chances of that thing happening good and the event is likely to occur.
24) There is a 20% chance of rain tomorrow. Unlikely.
A low chance of 20% means that something is unlikely to occur.