It might be said that the first lesson of the poem is to float on one´s back (option A) It seems that a father is teaching his daughter to swim on her back. This can be inferred by the use of certain words such as "Lie back daughter" "spread your arms wide". It also might be understood that the lesson is deep that that, It might suggest a father letting her daughter go, letting her be because she is going to be safe.
a note equivalent to two whole notes. 2 : a curved mark ˘ used to indicate a short vowel or a short or unstressed syllable.
Contractions are used to make words smaller but still be the same words...I don't know what a subjection is...
