15
1. sings 2. writes; is writing 3. are deciding
16
collect, museums, listen to music, CD disks, news, singers, favourite, programmes
17
There are three cushions on the sofa
There is a round table and eight chairs opposite the door
There aren't any tables in the bedroom
18
1. played
2. began
3. gave
4. wanted
5. finished
6. studied
7. visited