A.n≥p/2[p] B.n≥p/3[p] C.n≥p/4[p] D.n≥p/5[P]
A.3 B.4 C.5 D.6
A.短環(huán)鏈 B.長環(huán)鏈 C.撐環(huán)鏈 D.片狀鏈