Whether and weather

Whether is a conjunction used to introduce alternatives.

Rule 7

‘dis’ and ‘mis’

Never double the ‘s’ of these prefixes. When a second ‘s’ occurs, it is the first letter of the next syllable.

So we have

Rule 2

Short monosyllables always double their final consonant.

Shop, shopping (NOT shoping)
Let, letting (NOT leting)

Rule 3

‘ie’ and ‘ei’

English is said to have one of the most difficult spelling systems in the world. There are several reasons for this. 1) The pronunciation of many words has changed over the years, but not their spellings. For example, the ‘k’ in ‘knife’ and ‘gh’ in ‘right’ were pronounced during the Middle English Period (12th to 15th century). 2) Vowels have also changed their pronunciation over the years. 3) The spellings of many words have changed but not their pronunciation. For instance, the word ‘doubt’ used to be pronounced as ‘doute’. The ‘b’ was later inserted because the word had its origin in the Latin word ‘dubitare’ which had ‘b’ in it.

Again and again: frequently, repeatedly

We shouldn’t commit the same mistake again and again.

Now and again: once in a while, at times, from time to time, occasionally