Everymeans____triedoutbutneverwithsuccess,asfarasmyknowledgegoes.
C
【句意】就我所知，每种方法都试过了，但都没有成功。
【难点】means虽以s结尾却是单数形式，因此谓语动词应选用第三人称单数。
Thelittleboydidn’tknow_______.
My coat__________ there behind the door. Can ’t you see it?
The children should go to school instead of to support their families.
Sometimes a bus ____ gets on the bus to check the tickets.
Due to the bad weather the plane was ____ for two hours.