Four years have elapsed since he went to London.

自从他去了伦敦, 已过了四年。

Five months have elapsed since he joined the army.

"自从他参军以后,已经五个月了。"

A month elapsed, the girl was narcose all the same.The boy was peaked and pined, but he still believed that she would get better one day.

一个月过去了，女孩仍然，而男孩早已憔悴不堪了，但他仍苦苦地支撑。