a modern-day proBlem unknown in earlier times.
在从前不为人所知的现代的问题
To keep oneself or one's plans hidden.
隐匿使自己或自己的计划不为人所知
"The Best-known are syphilis, gonorrhea, AIDS, and herpes simplex."
最为人所知的性传染病有梅毒、淋
The science of intoning was unknown.
吟诵的学问还不为人所知。
A member of the indigenous or earliest known population of a region.
土著人一地区原始的或最早为人所知的人
To make an idea understood is to get it across.
要使一种想法为人所知就是要人理解它。
Surrounding the earth is a layer of air of unknown thickness.
环绕地球的是一层空气，其厚度尚未为人所知。
(used of information or news) kept secret by using influence.
（用来指消息或者新闻）利用权利使得不为人所知。
When one has a wide range of knowledge, one can then know the mandate.
知天所为，知人所为，然后知道，知道然后知命。
make known or acquainted.
为别人所了解或熟知。
His name was unknown to the world.
他的名字不为世人所知。
Well, Holland is famous for its tulips and windmills.
嗯，荷兰以郁金香和风车为人所熟知。
many of the best known edible crabs.
为人所熟知的可食用的螃蟹。
The music is known very well by people.
而这些曲调为人们所熟知，
clever Dick;( infml derog )person who thinks he is always right or knows everything
口,贬)自以为一贯正确或无所不知的人
It was erected before the time of living memory.
它建造的时间为人所不知。
Curling is another sport that is not as well known.
冰壶是另一项不为很多人所知的运动。
A man is know by the company he avoid.
看他所避的朋友，就可知其为人。