Getting apostrophes wrong, or omitting them altogether, can make your academic writing appear sloppy. It is important to learn and practise the two uses for an apostrophe.
Adding an apostrophe and then 's' to a word shows that the person or thing owns something. For example:
The government's decision has huge consequences.
Here the decision belongs to the government. If the original word already ends in 's,' the apostrophe is placed at the end, but with no extra 's.' For example:
Holmes' study support this idea.
Apostrophes also show where letters have been removed. For example, in the word 'don't' which is a shorter version of 'do not,' the apostrophe shows the omissions of the second 'o'.
Tip: What apostrophes cannot do is show that something is plural. This is a common mistake, The following is an incorrect example of apostrophe use: The study used twenty participant's from different ethic backgrounds. The 'participant' does not possess anything, and no letters have been omitted, so the apostrophe would be needed if you wanted to say, for example: At the end of the study, the twenty participants' scores were compared.
You hardly ever need to use an exclamation mark in an essay. It is intended to express feelings and emotions and is very rarely used in academic writing. You might use it if you were reporting the direct speech of an interviewee: The participant stated: "Frankly the benefits situation is driving me bonkers!" However, generally, it is best to forget the exclamation mark in your academic writing.