as a matter of course

　as a regular habit or usual procedure 例行地

　at risk

　in danger 处于危险中

　before you know it

　very quickly and suddenly 很快地

　clean up

　clean thoroughly and remove anything unwanted 清除

　come across (as)

　make an impression of ··· 给人以···的印象

　good old days

　periods in history or in one’s personal past, when conditions of life and work were better 往日的美好时光

　in / at the back of one's mind

　in one’s thoughts, but not of immediate or great concern 有···的意识

　in pursuit of

　with the aim of obtaining 追求

　in use

　being used 在使用中

　let ...down

　make unsuccessful by failing to achieve a good enough standard 使···失灵，使···不能发挥水平

　more often than not

　in most cases 经常

　pick up

　notice 注意到

　set in

　(something unhappy) begins and seems likely to continue 开始