Answer:
C). In the decade following the Civil War, tall buildings had just begun to emerge; and, although the skylines of the world's great cities were still dominated by church spires, there was increasing activity in the development of elevator apparatus adapted to the transportation of people as well as of merchandise.
Explanation:
The above sentence most aptly backs the advancement of key idea of 'advent of elevator system in United States and its spread.' The development of <u>'elevator apparatus adapted to the transportation of people as well as of merchandise' assisted in promoting the hotel operators to 'elevate their patrons for one or two floor above</u>' <u>for commercial gains that led the foundation of early elevator industry</u> that eventually kept on advancing with time. It reflects that how the apparent advantages of elevator system have played a significant role in emergence of tall buildings as well. Thus, <u>option C</u> is the correct answer.
Answer:
When I was four years old, my dad and I planted a tree in our front yard.
Until I turned 18 years old, Dad and I measured it every year on my birthday.
Explanation:
In the first example, the verb to plant is used in the Past Simple Tense. It is because the action, that the girl is talking about, has happened in the past, and there is a time order when I was four years old. This is a finished action with a finish time word.
In the second example, the verb to measure is used in the Past Simple Tense. It is because the action is repeating in the past and there is an expression every year. This tense is used for that this repeated action is now completed and took a place in a specific time in the past.