Prior () his departure, he wrote a letter to his mother.

单项选择题The owner of the store promised to give the money back to the traveller（）his return.

A.at
B.from
C.by
D.on

单项选择题Only after I left the place that how ugly and dishonest the people there had been.

单项选择题When the clouds moved in, the moon was no longer () sight.

单项选择题Going () sleep for a long time makes me feel very tired.

单项选择题If I had () in business, I might be a very wealthy man today.