It was not until mid-night _____ he went back home after the experiment.

I’m sure that if you make good use of your ______ time, your English will be improved in a short time.

________ everyone else wouldn’t go to the mountain area, he went without a second thought[ ]

I really don’t know ___ ___I kept the secret papers.

Will you go to the exhibition tomorrow?—YesI will go ____it’s windy