A practical english grammar - Vyssaja skola 1978

Adverbs of frequency
Sound symbols

These words answer the question how often? Those that are phrases occupy initial or final position (with a few restrictions).

Now and then the lightning flashed.

The lightning flashed now and then.

From time to time he puffed at his pipe.

He puffed at his pipe from time to time.

They go there all the time.

(All the time is not used initially.)

The one-word adverbs of frequency occur, preferably, in medial posi­tion. Almost all of them may occur there, but they occur readily in other positions as well. Below is a chart of the commonly occurring adverbs of frequency, with comments on restrictions on their position.

¹ Has a special meaning with the progressive; see Chapter 5.

² In ordinary language, ever is used in negative and interrogative contexts only.

³ When used in initial position, requires inversion of subject and verb: Never have I seen . . . , Seldom does one find, . . . etc. A formal usage.

⁴ May be used with inversion of subject and verb, but this is not required.

⁵ Once in initial or medial position usually means ’on a certain occasion’ rather than ’one time (and no more)’: Once I saw a bear, I once saw a bear. In final position it may have either meaning, according to the context.