—Do you know when he will come back?

—___________.[ ]

A. Once a week

B. For a week

C. Till a week

D. Not until next week

与少量水共研，能形成白色或黄白色乳状液的药材是（）

A．乳香

B．天然没药

C．胶质没药

D．原装血竭

E．加工血竭