Before the problem can be solved，it must be obvious ________ the problem itself is.(2011·湖南，31)
A．what B．that C．which D．why
His writing is so confusing that it's difficult to make out ________ it is he is trying to express.(2011·安徽，33)
A．that B．how C．who D．what
It is by no means clear ________ the president can do to end the strike.(2012·新课标全国)
A．how B．which C．that D．what
(2013·四川，6)________you said at the meeting describes a bright future for the company.
A．When B．How C．What D．That
(2013·安徽，21)From space, the earth looks blue.This is ________about seventy－one percent of its surface is covered by water.
A．why B．how C．because D．whether
(2013·浙江，16)The only way to succeed at the highest level is to have total belief ________ you are better than anyone else on the sports field.
A．how B．that C．which D．whether
