1．Though having discussed it for long, they still haven't reached an agreement ________ they should pour more money into the project.
答案：whether
2．A wonderful idea suddenly occurred to me ________ I would turn to the reference book to finish my homework.
答案：that
3．Evidence has been piled up ________ drinking water after getting up in the morning contributes to one's health.
答案：that
4．________ was known to us all that Johnson had broken his promise ________ he would give each of us a small gift.
答案：It; that
5．When the news came ________ the war broke out, he decided to serve in the army.
答案：that
6．I have no idea ________ size shoes she wears.
答案：what
