56. I found _______impossible for _______towork out the maths problem.

lady came _________ to the bus stop, only_______ the bus had gone

_____ my dictionary– Yes. I put it in your desk just now.

It remains unknown ____ the peace talk between the two countries is going to lead. [ ]

China Hengda＿well have won the football match, but I don’t know because I wasn’t there.