---Did you catch what the teacher said?

---No. She spoke so fast _______ I couldn’t hear her very clearly. 

A．which

B．that

C．when

D．since

中枢神经系统肿瘤放射治疗中，与放射毒性反应无关的症状是（）。

A.恶心

B.呕吐

C.腹泻

D.头痛

E.乏力