引起再障的最常见药物为( )
A．氯霉素B．他巴唑C．环磷酰胺D．西咪替丁E．利福平
参考答案：A
He was busy with his essay at that time. Otherwise he ____ over to help us.
A．had come
B．would come
C．would have come
D．was coming
疟疾贫血的原因有哪些？
