_______ difficult and challenging the task may be, we must finish it on time, because there is a possibility _______our work will go down in history.

 I’ll never forget the holiday ______ we spent together.

Many people _________ lose one of their senses have made great achievements.

–What did the young man come to your company for? -- He wanted a job, _____ he had never experienced before.

There were 20 people sitting in the room, half ___ were women.