She is too slow. She pass the test but she too little.A. would; knew B. will; knows C.

问题补充：

She is too slow. She pass the test, but she too little.

A. would; knew

B. will; knows

C. would; knows

D. will; knew

答案：

A. would; knew

B. will; knows

(答案→)C. would; knows

D. will; knew

解析：shouldn’t have come意为“本不应该来” ，暗含 “她来过了” 的意思，与题意不符；needn’t have to come中need为情态动词，倾向于主观上的“必要”，与题中给出条件“We had changed our plan”不符；didn’t need to come中的need to do表示“(有责任、有义务)做某事”，符合题意。