barrier n. 障碍
budget n. 预算 v. 做预算
cancel v. 取消 cancellation n.
capacity n. 能力，容量
category n. 种类，类别
challenge n.&v. 挑战
characteristic adj. 典型的 n. 特征
circulate v. 循环，流通 circulation n.
circumstance n. 情况，环境（复数）
clarify v. 澄清 clarification n.
collaborate v. 合作
colleague n. 同事
combine v. 结合 combination n.
comment n.&v. 评论
communicate v. 交流 communication n.
compare v. 比较 comparison n.
compensate v. 补偿 compensation n.
compete v. 竞争 competition n.
complex adj. 复杂的
concentrate v. 集中 concentration n.
concern v. 涉及；使担忧 n. 关切
conclude v. 得出结论 conclusion n.
confirm v. 确认 confirmation n.
conflict n.&v. 冲突
considerable adj. 大量的，相当的
consist v. 由… 组成 consist of
constant adj. 持续的，恒定的
construct v. 建造 construction n.
consult v. 咨询 consultation n.
contribute v. 贡献，促成 contribute to
convenient adj. 方便的 convenience n.
convert v. 转换 conversion n.
convince v. 使信服
cope v. 处理 cope with
correspond v. 符合，通信 correspond to