1. You can take the bus.

If somebody say the sentence, what does that mean?

2. You may take the bus.
3. You are able to take the bus.
4. You are allowed to take the bus.

What does usually #1 mean? #2, 3, or 4?

They all mean about the same -- but 1 usually means # 2.

#3 likely means that a bus goes where you want to go.

#4 is more often addressed to a child who's been given permission to take the bus.

1. When someone says "You can take the bus," it means that you have the ability or option to take the bus as a mode of transportation. It implies that taking the bus is a feasible or practical choice for you.

2. When someone says "You may take the bus," it means that you have permission or authorization to take the bus. This suggests that there might be certain rules or circumstances in which taking the bus is allowed or approved.

3. When someone says "You are able to take the bus," it means that you have the physical or practical capability to take the bus. This emphasizes your capacity to use the bus as a means of transportation.

4. When someone says "You are allowed to take the bus," it means that you have been given permission or clearance to use the bus. This indicates that there might be certain restrictions or regulations in place that dictate whether you can or cannot take the bus.

In summary, sentence #1 generally refers to the availability or feasibility of taking the bus, while sentences #2, 3, and 4 focus more on permission, capability, or allowance to take the bus. The meaning can slightly shift depending on the context in which these sentences are used.