8.24 using prepositional phrases and adjectives

For some statements about time, you can use a phrase consisting of 'when', 'while', 'once', 'until', or 'till', followed by a prepositional phrase or an adjective.

For example, you can say, 'When in Paris, you should visit the Louvre', meaning 'When you are in Paris, you should visit the Louvre'.

• He had read of her elopement while at Oxford.
• Man acquires great technological mastery of this world but, when under threat, reverts with terrifying ease to his primitive past.
• Steam or boil them until just tender.

You can use a phrase consisting of 'when', 'whenever', 'where', or 'wherever' and an adjective such as 'necessary' or 'possible'.

For example, you can say 'You should take exercise whenever possible', meaning 'You should take exercise whenever it is possible'.

• She had previously spoken seldom and then only when necessary.
• It paid to speak the truth whenever possible.
• Help must be given where necessary.
• All experts agree that, wherever possible, children should learn to read in their own way.