口腔检查应遵循的原则是()
A.由前至后
B.由外及内
C.由浅入深
D.上、下部位对比
E.健、患两侧对比
参考答案:A, B, C, E
He apologised to me for his ________ my letter.
A.delaying answering
B.delay to answer
C.delaying to answering
D.delaying to answer