Rearrange the following six sentences (A), (B), (C), (D), (E) and (F) in the proper sequence to form a meaningful paragraph: then answer the questions given below them.
(A) No one knows their names.
(B) With irrigation systems, farmers were able to raise more food with less labor.
(C) The first engineers lived in the middle East, probably around 3500 B.C.
(D) Today’s city, thus, is essentially still a place where specialists live and work.
(E) Thus, an increasing number of people were relieved of agricultural chores and able to gather in cities to practice specialties.
(F) However, they conceived and built the elevated irrigation canal.