Bryan Cho, 1. Okay 2. Okay 3. It is grammatically correct but the meaning has changed. The original sentence uses ‘to have’ as a causative verb. Subject + Have + Object + Past Participle 'Have' as a causative verb expresses the idea that the person wants something to be done for them. The correct form: When you have an important package delivered, notify the receiver that the package is on its way. 4. It’s grammatically correct but the meaning is different in the way that you stated. 5. It’s grammatically correct. 6. It’s grammatically correct, but the meaning has changed. The dependent clause with the present participle shows action happening at the same time as the verb in the main clause. PRESENT PARTICIPLE When having an important package delivered, you notify the receiver that the package is on its way. = You HAVE an important package delivered – you NOTIFY the receiver that the package is on its way. When having an important package delivered, you notified the receiver that the package is on its way. = When you HAD an important package delivered, you NOTIFIED the receiver that the package is on its way. Example: Working on the fundamentals of English grammar, his writing slowly improved. -The action expressed by ‘improved’ happened in the past at the same time the ‘working’ happened. PAST PARTICIPLE The dependent clause with the past participle shows action occurring earlier than the verb in the main clause. HAVING HAD an important package delivered, you NOTIFIED the receiver that the package is on its way. Having worked on the fundamentals of English grammar, his writing improved.

When having an important document delivered, notify the receiver that the package is on its way. This is a general order, it's assuming this is a rule that applies to everyone, as if it were listed on a sign. When you have delivered an important document, you notify the receiver that the package is on its way. This sentence is making an if-then assumption, (when you do this, this happens). When you deliver an important document, you notify the receiver that the package is on its way. This makes the same general assumption as the one before it. When you deliver it, when you have delivered it, they are very much the same. When delivering an important document, you notify the receiver that the package is on its way. Same They are all generally the same except the textbook sentence. When you omit (you), the sentence becomes more like an order. Notify becomes an order. You notify the... Becomes the action 'you' are taking, in some hypothetical circumstance. It is no longer an order but the verb 'you' are taking. When you is added, the sentence acts like it is stating a fact about human conduct even if it hasn't happened or might not happen. To place you in the sentence sort of allows the listener to imagine themself completing the task if they should ever do it, for future reference. Being an english speaker I didn't have to worry about what is present participle or not, I've heard of the term but I don't have a foggy idea of what it means. Through my native experience of the language though I can tell you what I feel is right and wrong. Your contrived sentences are all written correctly, they just mean something slightly different than the book.