expand/expansion

expand /iksˈpænd/ vi. & vt. 扩大，膨胀，加大：Our foreign trade has expanded during recent years. 近几年我们的外贸扩大了。When metal becomes hot, it expands.金属遇热膨胀。He expanded his short story into a novel. 他把他的短篇小说扩展成了长篇小说。 

expansion /iksˈpænʃən/ n. ［u］& ［c］扩大，膨胀，扩张：overseas expansion 海外扩张； expansion of territory 领土扩张 Heat causes the expansion of gases. 热使气体膨胀。