温经汤主治病证的病机是（）。

A.冲任虚寒，痰湿郁阻

B.寒凝血瘀，湿阻胞宫

C.冲任虚寒，带脉不固

D.阳虚血凝，瘀阻胞宫

E.冲任虚寒，瘀血阻滞

—Listen! There is a knock on the door．Who _____ it be?

—It must be Jack．Just now I sent for him．

A．shall

B．can

C．must

D．might