The skill of safe driving__ necessary to avoid collisions, which__ many thousands of people annually.

1.A '$pioneer^{\prime} is a/an :$

2.According to some studies, dolphins, whales and ¾ other sea creatures use highly sophisticated navigation systems.

3.We have to do some research in order to ¾ the possible factors that could affect the outcome of the project.

4.Many people who live near nuclear plants are concerned. __ go wrong, the impact on the surrounding area could be disastrous.

5.Supposedly, digital versatile disks, or DVD as they are called, are__ resistant to scratching__ records.

6.The government__ that the projects__ with great success.

7.These differences between the two photographs__ with the help of computer programs.

8.Salma could not tell__ books were \left on the table.

9.They like to keep their old houses rather than build new ones__ it is very difficult and expensive to maintain them.

10.Hydrogen peroxide__ as a bleaching agent because it effectively whitens a variety of fibres and surfaces.

11.__ can be grown on arid land.

12.There are three kinds of solar eclipses : one is total, another is annular, and__ .