四环素牙四环素主要沉积在下列哪一层()
A.釉质
B.牙本质
C.牙骨质
D.牙髓
E.釉质牙本质界
参考答案:B
“千古奇冤,江南一叶,同室操戈,相煎何急”是为皖南事变而作的题词。其作者是______。
A.叶挺 B.周恩来 C.陈毅 D.毛 * *
---Can you tell me ________ , Tom?
--- Some stories in the newspaper.
A. when you read
B. what you read
C. how you read