________ of the city was covered with the heavy smog.

Metal ______making machines and many other things.

There used to ________ a clean river in the village, but now it’s dirty.

I’m a little weak in Maths. I don’t know how to improve it. — Why not __________ Daniel for help? He’s very good at it.

When were you born?—I was born __ January ,1987.[ ]