—Mum, I’m sad because I failed my exam again. —Don’t give up. ________ hard and you’ll succeed in th

20.—Mum, I’m sad because I failed my exam again.
—Don’t give up. ________ hard and you’ll succeed in the end.
A. Studying B. To study C. Studies D. Study
【答案】D
【解析】
【详解】句意：——妈妈，我很悲伤因为我又在考试中失败了。——不要放弃。努力学习这样你最后就会成功。A. Studying    学习，动名词；B. To study学习，动词不定式；C. Studies学习，第三人称单数；D. Study学习，动词原形。这里是祈使句，动词原形开头，祈使句+and+陈述句。根据题意，故选D。