Help with general Writing Rules

<p>Hey guys, I signed up for the test in this upcoming June and I feel really prepared for it but the writing section is always mercurial for me since I'm not a native speaker. Sometimes I would do perfectly fine and miss around 2 questions and then sometimes I would miss 7 questions and most of these came from sentence completion part, it would be really helpful if someone can enlighten me on these topics.
1. When should I use Having or Because at the start of the sentence? I see a lot of questions about this and I would miss them 50% of the time because I would just guess between those two.
2. What should comes after a comma if an Object started the off the sentence. Ex: "Watermelons have been cultivated for more than 4000 years, THUMPING THEM AS A WAY to test for ripeness has an equally long history" The correct answer was And Thumping Them. I've seen the verb-ing as the answer when an object started off the sentence but then in some cases like this one, and comes before the verb-ing. What should my general rule be when doing these kind of problems?
3. The last topic that has always been on my mind is when to use a semi colon and how it should be used. Is it used after a point is made and that point is made in a complete sentence then a semi colon is followed so that the next sentence is relevant to the point that's been made before? Also, can you start off sentences that come before a semi colon with However, Therefore, Consequently plus the addition of "it" because I feel like it is vague but since it's a semi colon sentence, people will know "it" means from the sentence that precedes it. </p>

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<li><p>This is a bigger question, but you can start a sentence with “Because” when the sentence begins with a dependent clause (an independent clause + a subordinator–like “because” or “when,” for example). That dependent clause will be followed by a comma and an independent clause: Because I lost my marbles, I was committed to an asylum against my will.</p></li>
<li><p>Learn about clause rules and coordination/subordination. Independent clauses may not be joined by a comma–they may be joined by a semicolon, a semicolon and a conjunctive adverb (like “however”), or a comma and a coordinating conjunction (FANBOYS–for and nor yet or but so).</p></li>
<li><p>Semicolons must have independent clauses on both sides. The independent clause following the semicolon may begin with a conjunctive adverb (however, consequently, etc.–think of them as the “fancy” conjunctions) and a comma.</p></li>
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