Have scientists found life on Mars?
Not yet, but I think they ______ it some day.( )
A.findB.foundC.have foundD.will find
________ great scientist Qian Xuesen is!
()I think _______ necessary for you _______ breakfast.
The workers were made _____ the whole day.
He often plans_________ a very relaxing vacation. A. having B. have C. to have
His father advised me _____ it again.