Rewrite the following general statements using singular nouns. Make sure that the verbs agree with their subjects. For example:
Engineers must be familiar with computers.
An engineer must be familiar with computers.
Trees produce oxygen.
A tree produces oxygen.
1. Automobiles should be kept in good repair.
2. Bats locate insects by means of sonar.
3. Diplomats should, if possible, be multilingual.
4. Hats are useful in cold weather.
5. Physicists must study a great deal.
6. Elephants can be dangerous.