"倒计时"一般用countdown，如“距离世界博览会倒计时100天的”可以表达为the 100-day countdown of World Expo。
countdown
英 [ˈkaʊntdaʊn] 美 [ˈkaʊntˌdaʊn]
n. 倒数读秒，倒计时;大事临近的时期;准备过程，准备工作
例句：
1、The countdown has begun for the launch later today of the American space shuttle
美国航天飞机的发射已于今天晚些时候开始进入倒计时。
2、There were three more things to do before countdown.
开始倒计时之前还有3件事要做。
3、The countdown to the Notting Hill Carnival is in its final hours.
诺丁山狂欢节已经进入了最后几个小时的倒计时。
4、The countdown to Christmas has started.
圣诞节倒计时开始了。
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5、I can slow down the countdown.
我可以让倒数慢下来。
"剩余"的英文有surplus; residue; remainder; overplus。
surplus
英 [ˈsɜ:pləs] 美 [ˈsɜ:rpləs]
adj. 过剩的;多余的
n. 盈余;顺差;剩余额;公积金。
例句：
1、Germany suffers from a surplus of teachers.
德国遭遇了教师过剩的问题。
2、Few people have large sums of surplus cash
几乎没人手头很富裕。
3、Japan's annual trade surplus is in the region of 100 billion dollars.
日本每年的贸易顺差额在1,000亿美元左右。
4、I sell my surplus birds to a local pet shop
我把多余的鸟卖给当地的宠物商店。
5、The houses are being sold because they are surplus to requirements.
这些因超出需求而闲置着的房子正在出售。
residue
英 [ˈrezɪdju:] 美 [ˈrezɪdu:]
n. 残余，残渣;余渣，残余物;[法]剩余财产;[林]废材
例句：
1、Always using the same shampoo means that a residue can build up on the hair.
总是用同一种洗发水就意味着某种残留物会在头发上越积越多。
2、A residue can build up on the hair shaft, leaving the hair limp and dull looking.
残留物会积聚在头发上，使头发看起来软塌塌的，而且毫无光泽。
3、This paper studied the fast determination method of SO2 residue in edible fungus and its affected factors.
对食用菌中SO2残留的快速测定方法及各种影响因素进行了研究。
4、The effectiveness of agricultural disposal and utilization of fermentation residue was studied in plot experiment.
通过田间小区实验，对生物发酵残渣农业处理和利用的效果进行了研究。
5、Suspension bed hydrocracking technology and water soluble catalyst were used for upgrading of atmospheric residue from Dagang oil field.
采用悬浮床加氢技术和水溶性分散催化剂对大港常压渣油进行了轻质化和改质研究。
residue
常见释义
英[ˈrezɪdjuː]
例句
模p剩余系中的一个分布性质
A Distribution Property of Residue System Modulo p