State whether ing-forms are gerunds, verbal nouns or participles.
1. During the last hundred years many new methods of observing cells have been discussed.
2. After Newton’s discovering the law of universal gravitation many people became interested in mathematics.
3. In losing an electron, a neutral lead atom becomes positively charged.
4. Hybridization, used in conjunction with selection, presents the greatest possibilities for improvement of plants by breeding at the present time.
5. The fact having been established, the chemists began investigations in search of methods of extracting sugar from beets.
6. In other air breathing forms the organs of respiration are tracheas, ramifying tubes which open on the surface, their finest branches extending in all parts of the body.
7. After cotton flowers open, a period of 45 to 70 days passes before the balls open, with the length of time being determined by the variety, temperature, humidity.
8. In most biology text-books the entire living world is divided into two groups: ”plants” and “animals”. The microorganisms are somewhat arbitrary divided between the two groups, the protozoa being classified as animals and the algae and fungi as plants.
9. Mastering a foreign language thoroughly is not easy.