—I did not give offence to you ___________.—Forget it. Let’s make up.

  -----When will they come back? 　　-----I _____ don’t know.

It’s too late to go to the basketball match now;         , it’s beginning to rain.

Recent studies have discovered that fathers uniquely contribute to the development of their children, _____ in low income families.

I often thought of my childhood,             I lived on a farm.