Though great efforts have been    ___  on their study , Annie still can’t make any improvements , which

makes her parents greatly ______ . [ ]

A. made ; disappointed      

B. done ; disappointing

C. taken ; disappointed      

D. given ;disappointing

下列因素中，对反应Fe³⁺(aq)+3SCN^—(aq)Fe(SCN)₃(aq)的速率不产生显著影响的是

A．浓度　　

B．温度　　

C．压强　　

D．反应物的性质