A:①和②
B:③
C:④
D:以上都不对
Jack Ripper was ________ for murdering many people in the nineteenth century.
乙烯利(化学式为C2H6ClO3P)是一种优质高效植物生长调节剂,具有促进果实成熟等效应。每个乙烯利分子中含有____个原子。
Which of the following is not the city of the USA?