1. The letters f, l, or s at the end of words of one syllable and after a single vowel are usually double; as, muff, ball, grass.

2. Words ending in e usually drop it on adding ing or any other suffix beginning with a vowel; as, come, coming; bride, bridal; love, lovable.

3. Words of one syllable, and words accented on the last syllable, if they end in a single consonant with a single vowel before it, usually double the final consonant on adding ing, ed, or any other suffix beginning with a vowel; as, rob, robbed; mad, madden; admit, admitting; begin, beginner.

4. Words in y with a consonant before it usually change the y into i when a suffix not beginning with i is added; as, cry, cries, crying.

5. The apostrophe (') is used to indicate the omission of one or more letters; as, didn't for did not; can't for cannot; let's, let us; I'm, I am; you're, you are; isn't, is not.