10.Every means ____ tried but without any result.
“either,neither,each,every 或no +单数名词和由some,any,no,every构成的复合不定代词,都作单数看待.如：Each of us has a new book./ Everything around us ismatter.” 但是这里并不是单数名词呀?这不是很奇怪么?答案是has been