It is important to test products on animals before releasing them commercially to markets.
The problem here is that there are two kinds of market – physical and virtual – and in this example, markets (plural) suggests more than one physical market, while releasing them commercially suggests more than one virtual market. Let’s take a look at some examples.
These are the places you go early in the morning to buy cheap vegetables. Often this kind of market is outdoor:
If it’s an indoor market then it’s usually inside a large hall:
The featured image for this post shows people buying and selling things on the virtual market. They’re not buying anything inside that building, rather they are investing in things that are located elsewhere so that they can hopefully receive some of the profits from the sale of those things.
A particular virtual market or set of virtual markets may be mentioned explicitly:
Sometimes more than one virtual market is implied:
And sometimes a specific virtual market is implied but not mentioned explicitly:
If the name of a virtual market is not given, certain phrases can suggest that you’re talking about a virtual rather than a physical market.
If it’s on the market (one or more virtual markets), it’s not at the market (a single physical market).
Our opening example implies a set of virtual markets that are not explicitly mentioned, and so we need: