The scientist corresponds with colleagues in order to learn about matters ______ to her own research.
His sister left home in 1998, and ____________ since.
We are not ready to go into production yet, for the new switch mechanism isn’t fully ______.
Helen always helps her even though going to school ________ most of her day.
The policeman came up to the house, whose door was open, ________ there for a while, and went in.
—Too noisy outside! I just can’t focus on my study. —______. Let’s go outside and play soccer instead.