-Has Tommy finished his homework yet?

-I have no idea; he ____ it this morning.

A．was doing

B．had been doing

C．has done

D．did

肺虚喘证其特征是（）

A.喘急胸闷

B.喘促气急

C.喘咳气涌

D.喘促气短

E.动则喘甚