A.Its resin (树脂) isn't poisonous.
B.It can shoot its resin a great distance.
C.Its leaves have no veins.
D.It doesn't need much water to grow well.
A.By cutting a path all the way across the leave.
B.By eating only the stem of the plant.
C.By changing the plant' s chemistry.
D.By eating only at night.
A.Their literary value.
B.The debate over who wrote them.
C.The time period in which they were written.
D.Why they are still popular today.