（）是指停药后血药浓度已降至阈值以下时的残存药理效应
A.药物副作用
B.毒性反应
C.变态反应
D.后遗效应
参考答案：D
食管、胃底曲张静脉破裂出血，一次出血量最多常达（）
A.200～300ml
B.300～400ml
C.400～500ml
D.500～1000ml
E.1000～2000ml
The "contract" appearing in Paragraph 4 is quite likely referring to ______.
A．an arrangement between USA TODAY and the "Freedom of Information Act"
B．a commercial agreement between the Bush administration and Mr. Armp Williams
C．an arrangement between the Education Department and the Ketchum public relations company
D．a volunteer agreement between Mr. Armp Williams and the No Child Left Be hind effort
