A.
B.
C.
D.
[单选题]A.B.C.D.
[单选题]( ).A.B.C.D.
[单选题]A.-3xB.3xC.-12xD.12xE.6x
[单选题]A.塑料牙B.C.烤瓷牙D.瓷牙E.无尖牙
[判断题]A.对B.错
[单选题]A.B.D2.54C.D.