Many trees and flowers _____ in our school last year, and they made our school a beautiful garden. [ ]

A. plant

B. planted

C. have planted

D. were planted

叶粉末经微量升华得油状物，加硫酸2滴及香草醛结晶少量，初显黄色至橙黄色，再加水l滴，即变紫红色的药材是（）

A．.薄荷

B．广藿香

C．穿心莲

D．荆芥

E．青蒿