"Also" causing ambiguity.

I've taken the following passage from American Heritage Book of English.

also used ambiguously. Also shares with only the virtue of modifying the parts of the sentence to which it is closest, but this can sometimes lead to ambiguity. In the following examples, the sentence containing also is exactly the same, but in each example it modifies a different part and creates a different meaning:

1. I read in the paper that their band was coming to town. I also heard that the band would play here.
2. Mary heard that their band is coming to town. I also heard that the band would play here.
3. The band has been playing out on the West Coast for weeks. I also heard that the band would play here.

It’s a good policy to check that the context is sufficiently clear to limit the meaning of also so you won’t be misunderstood. If you’re in doubt, try moving also to another position and see if the meaning is less ambiguous: I heard that the band would also play here.

What i couldn't understand in this passage is how also in the above three examples modify different parts and creates different meanings.

GB