I don't think you can work out the maths problem ____ the teacher's help.

A．since

B．unless

C．because

D．without

外感秽浊与热毒之邪相合的舌象是（）

A.白腻苔

B.黄腻苔

C.积粉苔

D.灰黑苔

E.腐苔