Yeah, the point of having a range of grammar is that you are showing the examiner that you have a rather deeper understanding of English. Now, it's not always appropriate to use the passive voice, for example. In fact, Bill Gates doesn't like you're using it at all. You might notice when you're using word that there'll be a little squiggly line coming under a passive, and they'll suggest you use the active voice. But in some, for example, a process in academic task, one where something is being done to something else, then it's quite natural to use the passive. Think about... I'm glad that this person mentioned conditionals, because this is a good example of a complex sentence. You know, if the government does this, then there will be benefits for society. But think also about relative clauses. This is a thing which needs to be corrected. Many people who are benefiting from this will find another solution. Think about those things. Think about participle clauses. There are many different structures. You don't have to go wild because, just talk to Ernest Hemingway, Jimmy. He will tell you that a simple sentence is perfectly good, but for the sake of the test, show the examiner a little bit of complexity as well.