this bike is ______,if not better than,that one

題目：

this bike is ______,if not better than,that one
A as good as
B so good as
C better than
D as good
我認爲選D

解答：

絕對選A,if not better than在句中是插入語,其典型標誌是用兩個逗號隔開,起補充說明作用.完整的句子應該是this bike is as good as that one.