You should know the effective language to talk about the probability of something or the timescales in which things happen. It is easy to include some of the qualifiers in your ideas, to show that you have thought about the probability and/or timescales of the events. Some of the straight forward ways are;-

ultimately (= eventually, finally) rapidly soon potentially long term immediate  X may possibly happen  X will gradually/steadily happen  X will suddenly happen  
X will inevitably happen (= it cannot be prevented)  X will undoubtedly happen  X will happen step by step  X will spontaneously happen (= without outside help)  

In your answers, try to include some of these qualifiers; this is a way to improve the examiner’s perception of your writing skills and knowledge over grammar.

Let’s see some examples:-

Band 9 Task 2 essay (Sentence Fragment)

This, decreases the problem but will cause a great loss to the ethnic groups and culture

Band 9 Task 1 academic sample (Sentence Fragment)

The number will rise to its upper limit in 2010 before declining by 20%.

NOTE: Use it only for future prediction (if given).

Band 9 Task 1 letter (Sentence Fragment)

Here is an idea. When you get here, let’s have an early night so that you get over the jet lag, and then we will go to the downtown area in the morning. We can have a traditional breakfast at one of the old cafes, and see some of the sights. I think we might need another early night after such a long day!