Since I knew how hard the life they lead is, I have understood ____ they need so much money.

If you smoke a cigarette every day, you will _____ become addicted to smoking．

．Jack’s room always has the awful smell of an apartment whose windows are________opened.

I sincerely regret that I have hurt your feelings, but I didn’t do it ______.

I’m worn out,____,the bike doesn’t work well,___ I can’t go further.