题目

 On Sundays, rather than _____at home, I prefer _____ . A. stay; to travel             B. to stay; to travel C. stay; travel                   D. to stay; traveling 答案：A补充下面的裂变方程U+ n→  Sr+ Xe +（     ）氢弹中用氘核和氚核合成氦核，写出核反应方程________________________________．