They _______ the train until it disappeared in the distance.
---Do you mind if I open the door ? --- ____________.
This kind of CD-ROM is very popular. Why not buy one before it________ ?
The old man is _____ in a lonely house, but he doesn’t feel_____.
--- Why not go to see the dolphin show with me?---Because I _____ it.
Jim______ to the shop. He’ll be back_____ an hour.