There might be many reasons. What an author may right depends on the piece of literature written.
TenseDescribes...How to Form ItExamplesPresent action occurring in the present use the first principal part of the verb, or add -s or -es I run, she runs, they swim, you swim, dad launches, Paul watches Past action that already occurred and is no longer occurring for most verbs, add -d or -ed I ran, she ran, they swam, you swam, dad launched, Paul watched Future action that will take place in the future use the helping verb will or shall with the present verb tense I will run, she shall run, they will swim, you shall swim, dad will launch, Paul will watch Present Perfect action completed at some indefinite point in the past, or that started in the past and is still occurring add has or have to the past participle I have run, she has run, they have swam, you have swam, dad has launched, Paul has watched Past Perfect action that was completed before some other action in the past add had to the past participle I had run, she had run, they had swam, you had swam, dad had launched, Paul had watched Future Perfect action that will take place before another future action add shall have or will have to the past participle I will have run, she shall have run, they shall have swam, you will have swam, dad will have launched, Paul shall have watched
TenseDescribes...How to Form ItExamplesPresent action occurring in the present use the first principal part of the verb, or add -s or -es I run, she runs, they swim, you swim, dad launches, Paul watches Past action that already occurred and is no longer occurring for most verbs, add -d or -ed I ran, she ran, they swam, you swam, dad launched, Paul watched Future action that will take place in the future use the helping verb will or shall with the present verb tense I will run, she shall run, they will swim, you shall swim, dad will launch, Paul will watch Present Perfect action completed at some indefinite point in the past, or that started in the past and is still occurring add has or have to the past participle I have run, she has run, they have swam, you have swam, dad has launched, Paul has watched Past Perfect action that was completed before some other action in the past add had to the past participle I had run, she had run, they had swam, you had swam, dad had launched, Paul had watched Future Perfect action that will take place before another future action add shall have or will have to the past participle I will have run, she shall have run, they shall have swam, you will have swam, dad will have launched, Paul shall have watched
Answer:
Well, your question does not make sense but if you are asking about a garage sale sign ? then here are a few pics....
