油脂和淀粉的组成中都只含有 [ ]
A.碳元素、氢元素
B.碳元素、氧元素
C.氢元素、氧元素
D.碳元素、氢元素、氧元素
D
对于病因不明的化脓性脑膜炎，首选治疗是
A．头孢三嗪或头孢噻肟
B．大剂量青霉素
C．大剂量氨苄青霉素
D．青霉素+氨苄青霉素
E．氯霉素
Anita: I saw Nora in the teacher's office this morning. Do you know _______ she was there?
Brian: She cheated on tests.[ ]
A. how
B. if
C. when
D. why
