This section is from the book "Lessons In English", by Chestine Gowdy, Lora M. Dexheimer. Also available from Amazon: Lessons in English.
Verbs are sometimes inflected to show whether the subject represents one or more than one. (Explain why the word sometimes is necessary in the last sentence).
Verbs whose subjects represent but one are said to be in the singular number.
Verbs whose subjects represent more than one are said to be in the plural number.
In some cases singular and plural forms are alike.
Assert your present happiness. Assert to some one else his present happiness. Assert Mary's present happiness. What verb did you use forms of? How many different forms did you use?
Assert praising as a present act of yourself, using a form of the verb praise only. Assert it to some one else as his present act, using a form of the verb praise only. Assert it as a present act of Mary. How many forms of praise did you use? Assert praising as a past act of yourself, using a form of the verb praise only. Assert it to some one else as his past act. Assert it as a past act of Mary. How do the verb forms compare?
 
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