OK, let’s take a look at a few prepositions, and a really easy way to remember how to use them.
- to / from
In task 1, you will use “to” if you are talking about change. So, if something goes up or down, we use “to”. Look at the example:
The number of people rose to 800,000 in 2011.
So, we use “to” for changes, and we use it to describe the second number – the number at the end of the increase / decrease.
We also use “to” with “from” – like from 400,000 to 800,000 – again, we are talking about the end number. If we want to talk about the start number, we use “from”.
We use “by” similarly to “to”, so when we talk about change. This time, however, we are thinking about the difference between point A and point B. Here’s another example:
Number of people, 2001 = 55
Number of people, 2005 = 60
The number of people rose by 5 from 2001 to 2005.
So, we also use “by” for changes as well, but to talk about difference.
We use “at” to talk about numbers that haven’t changed over time. Look at this example:
The number remained steady at 25 for about five years.
So, “at” is used in the opposite situation to “to”.
We use “with” when we just want to talk about one number, at one time, with no changes. Here’s an example:
The highest number was in the 16-25 age group, with 500,000.
So, here’s the simple way to remember:
to – change, second number
from – change, first number
by – change, difference between first and last
at – no change over time
with – one number, no movement in time