1. They have fifty thousand troops along the border ready to repel any attack. 他们沿边界有5万军队，随时准备击退任何进攻。
2. Ants store food, repel attackers and use chemical signals to contact one another in case of attack. 蚂蚁储存食物，击退攻击者，并使用化学信号联系彼此以防被攻击。
3. After people have learned that magnets attract things, centuries passed after they took note of the fact that magnets sometimes also repel things. 在人们了解到磁铁能吸引事物之后，几个世纪过去了，他们才注意到磁铁有时也会排斥事物。
4. Pakistani president Pervez Musharraf said yesterday there was no danger of the country going to war with neighboring India, but that Pakistani forces would be ready to repel any aggression. 巴基斯坦总统穆沙拉夫昨天表示，巴基斯坦没有与邻国印度发生战争的危险，但巴基斯坦军队将做好准备击退任何侵略。
