问题补充：
Mr Zhang encourages the poor students study.
A. not giving up
B. to not give up
C. not to giving up
D. not to give up
答案：
A. not giving up
B. to not give up
C. not to giving up
(答案→)D. not to give up
解析：句意：张先生鼓励这些贫困的学生不要放弃学习。考查短语：encourage sb. not to do sth. 鼓励某人不要放弃做某事。 故选D
