Wow, what a nice computer you have bought!—Yes, it is of _____ to me, but I must say it also cost me a lot.

Look! ______ ducks are coming here.

You can hardly imagine the once clear canal _____ so seriously polluted that no fish can live in it. [ ]

With the advances of technology, plastics have taken the place of many ________ materials.[ ]

Why do you drink so much coffee?—Well, _______ it doesn’t keep me awake in the night, I see no harm in it.