161. at, in (表地点)  

at小地点;arrive at a small village
in大地点 例:arrive in Shanghai

162. at work, in work  

at work在工作,在上班;例:Both my parents are at work.
in work 有职业,有工作

163. increase to, increase by  

increase to增长到……;
increase by增长了…… 例:The number increased by 2,000 to 5,000.

164. at ease, with ease  

at ease舒适地,安逸地;
with ease容易地,无困难地 例:do it with ease

165. day after day, day by day  

day after day日复一日(无变化);
day by day一天天地(有变化)例:Trees grow taller day by day.