【C9】A．developingB．developedC．developD．developments

A.developingB.makingC.discoveringD.growing

【C17】A．proposedB．developedC．suppliedD．offered

【C19】A．advancingB．developedC．matureD．settled

【C20】A．improvedB．developedC．worsenedD．impaired

【C8】A．proposedB．developedC．suppliedD．offered

56._________A. developedB. less developedC. undev