I think its °while she was doing her homework°
Sedative is to anesthesiologist as capital is to a "D.corporation". This is primarily because sedatives are used by the former to achieve their goals and capital is used by the latter.
The punctuation mark that should be placed after the close quotation mark is a period. A period is used at the end of the sentence to indicate where the sentence fully stops. In the example given above, it is made up of two complete sentences with different thoughts each. Therefore, it should be written like this: I understand that "time is of the essence". I just need to find my keys so we can leave!
B.) Garden
this is because "on" is one of many words that are commonly in prepositions. Then to find the object of the preposition, you have to ask yourself, "on {or insert whatever your word is here} what", because the object of your preposition is the subject of the preposition. :)
I hope that makes sense!