Mr. Lee has worked in a bookshop _______he left college in 2007.

It was the second time we _____ in holding such important parties

Doing some running every morning can make you full of _______, I think.

Professor Backman took up scientificresearch for decades，and this is________he devoted all his life to.

He is so busy with the research _____ he has no time left for any other activity.