Answer:
B) Keep to the left side of the path.
D) Watch out for sudden sprays.
E) Do not walk on the grass.
Explanation:
These are telling you to do things, or are commands.
This one: "A. While playing my electric guitar, the amplifier went dead"
It seems to suggest that the amplifier was playing the guitar, which, of course is absurd.
The sentence could be changed in this way: "While I was playing my electric guitar, the amplifier went dead". Further, I think it is better use "when" instead of "while", but the important thing here is to note the dangling modifier.
Yes that is correct. All waves have wavelength, frequency, REST POINT, and speed. The FREQUENCY of a wave remains constant if the medium, temperature, and pressure do not change.
