To her joy Della earned first the trust of her students and then of her colleagues.A. o

问题补充：

To her joy, Della earned first the trust of her students and then of her colleagues.

A. one

B. ones

C. those

D. that

答案：

A. one

B. ones

C. those

(答案→)D. that

解析：考查指示代词。句意：让她高兴的是，Della先赢得了她的学生的信任，接着赢得了她的同事的（信任）。one泛指可数名词，意为“一个”；ones“一些”；those指代复数；that指代不可数名词。这里指代trust，trust是不可数名词，应该用that。故选D。