1. I can't see through a door.
2. I can swim in the river.
3. I can't ride a bike.
4. I can use skateboard.
5. I can't swim acriss the ocean.
6. I can't lift a double-decker bus.
7. I can't clap your hands behind your back.
2) 3 - b; 4 - a; 5 - b; 6 - a.
3) You are not reading the newspaper at the moment.
She is not playing football now
He is not cooking lunch at the moment.
It is not eating now.
They are not listening to music at the moment.