1. A single feather was found attached to a flap track on the wing and will be examined by experts at the Smithsonian Institution.
2. The two trains collided Friday afternoon on a stretch of single track in heavy fog, leaving the forward cars of the passenger trains a jumble of torn metal.
3. An ETF is a basket of securities designed to generally track an index, yet trades like a single stock.
4. single track
4. China is on track to overtake Germany as the group's largest single market this year.
5. The accident happened Tuesday when an apparent signalling blunder between separate stations allowed the trains on to a single track.