Insects feed _____ plants.[ ]
A. at
B. to
C. on
D. for
答案：C
But why _____ some bananas? [ ]
A. not buy
B. don't buy
C. not you buy
D. don't
根尖周囊肿衬里上皮的组织主要来源是（）
A.结合上皮
B.Malassez上皮剩余
C.牙 * *
D.缩余釉上皮
E.Serres上皮剩余
