从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并将答案填写在答题卡上
16. _____ hearing the good news, they all jumped up with joy.
A. At B. On C. In D. As
17. My father ________ take a nap after supper, but now he’s _____taking a walk.
A. got used to; used to B. used to; used to
C. used to; got used to D. got used to; been used to
18. The final exam is coming; all the students _____ it.
A. are prepared for B. are preparing
C. are preparing for D. are making preparation
