b) mineral water is sold in plastic bottles.
c) this room isn't used very often,
d) the letters are delivered at 8.00.
e) the classrooms are being cleaned now.
f) the Internet is used all over the world.
g) the road is being repaired at the moment.
h) the tests are being marked.
i) the computer isn't being used.
j) the washing up is being done.