Only one out of ten people..

Only one out of ten people___to handle the work at hand in the office properly,the rest will be assigned some simpler work
A has trained
B have trained
C have been trained
D are to be trained

我选C,为什么答案是D呢?不明白~~ 请教,谢谢

one out of............... one out of fifteen of thesebottles是什么意思？ keep one's nose out of one sample out of one thousand是什么意思呢 翻译一下：only to drive their employer out of business Tom is the only one of the students who____to Shanghai. She is the only one of the teachers___loved deeply. She is the only one of the students_______England？？ one of 和 the only one of 从句的谓语动词单复数有什么不同？ go out of one's way 什么意思?