Much to the couple's comfort，their income is now double ________ it was five years ago.
A.that B.if C.which D.what
As days go on，I think that Beijing will become ________ the whole world pay close attention to.
A.where B.what C.which D.that
Thinking that you know ________ in fact you don't know is a serious mistake.
A.what B.that C.when D.however
His mother did _______ she could ______ the boy.
A.what help B.that help C.what to help D.that to help
_______climber gets to the top first will get a ￥5,000 prize.
A.No matter when B.Whichever C.No matter which D.Whenever
When the news came ___ the war broke out , he decided to serve in the army.
A.since B.which C.that D.because
