It was until dark ___ he found ___ he thought was the correct way to solve the problem.

A. that; what      B. that; that            C. when; what     D. when; that

It was until dark ___ he found ___ he thought was the correct way to solve the problem.

  A. that; what       B. that; that          C. when; what       D. when; that

It was until dark ___ he found ___ he thought was the correct way to solve the problem.

It wasn’t until dark _________ he found _________ he thought was the correct way to solve the problem.

A. when , that             B. that , that                         C. when , what  D. that , what

It was not until dark _____he found _____he thought was the correct way to solve the problem.   

A.that; what        B.that ;that       C.when; that       D.when ;what