Radium salts，which have been found to ______ in bones，give rise to bone cancer.

A good friend is a person _______ we Turn for help when we are in trouble.

I would have come earlier, but I _____ that you were waiting for me

She won the first prize, though none of us had ____________ it.

ane is lucky to have got the well-paid job.一Yes, ＿＿she is inexperienced and young.