1. One of the worlds worst space flight disasters occurred on 28 January 1986, ---- the shuttle Challenger exploded soon after take-off, killing the crew of seven.
2. Meteorites are extraterrestial complex rocks with roughly equal amounts of metal and silicates ----.
3. Many Egypts ruins are unfortunately being destroyed by the very people ____ .
4. Galileo originated the method of controlled experiment _____ now forms the basis of scientific investigation.
5. It is not unusual for advertising campaigns even before the new products _____ onto the market.
6. Bennetts novel the old Wivess Tale is the one ____ he is likely to be best known by posterity.
7. Pharmaceutical companies are unlikely to develop a vaccine for an uncommon disease like leprosy ____.
8. At concert halls, the centre of the stage is increasingly being taken over by percussionists ____.
9. ., where they ate mosquito larvae and so helped prevent malaria.
10. , to whom they report.